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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time .
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what is an electron transport chain and how does it works ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time .
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how does nadh release an electron ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before .
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why does the body prefer to have energy stored in atp rather than nadh or fadh ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane .
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how does the mitochondria divide in to two mitochondria ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha !
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why is there lactic acid and ethanol building up in muscles ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins .
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where did the acytal coenzyme a go ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell .
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what are the differences between the calvin and krebs cycle ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved .
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what happened to that hydrogen atom after it left the water molecule ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever .
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why is 38 atp the best case scenario ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid .
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why ca n't our body make any more atp after we get enough our body needs ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s .
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what is the full form of fadh2 ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp .
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my teacher said that there are 38 atp produced when glycolysis is taking place but also said that 2 atp is lost during the cycle ( when it goes from cytoplasm to inner membrane of mitocondria ) , , so what he said is true or false ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there .
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so my text book is right or nadh is right ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt .
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how does yeast produce alcohol ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before .
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can energy be spent in any other form except atp ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle .
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which organelle is involved with cellular respiration ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha !
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what metabolized lactic acid and how does it works ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again .
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why is it more efficient for cells to have a small supply of atp on hand ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups .
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what does the rearrangement and decarboxylation of citrate do ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again .
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if the thing that creates atp to make atp , where does that atp come from ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released .
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what is the difference between organic and inorganic phosphate ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again .
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if prokaryotes makes atp in their cell membrane , how can they make proteins of making atp ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before .
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is there another energy source of energy other than atp ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen .
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if we put atp molecules in one place , will it explode because it releases energy ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen .
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can molecules other than glucose be used to make atp in the mitochondria ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before .
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if the person is fasting the cell will generate the same amount of energy ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane .
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what is meant by the electrons being `` swapped '' for protons ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen .
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how much atp would be made if you ate one piece of bread and then went dancing later ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp .
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so if i was to eat one gram of sugar how much would go into making atp ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell .
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what about the stage between glycolysis and the citric acid cycle called the preparatory phase ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell .
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is glycolysis related to hydrolysis ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again .
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if an animal cell performs anaerobic respiration , how many atps will it make ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages .
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i do n't think it would be the same because isnt the only part of the respiration prcess that the cell can do is glycolysis ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you .
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what are the steps in the energy cycle ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way .
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is there any differences between enzymes and co-enzymes ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar .
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why do people refer to atp as the currency of biological energy ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat .
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what is the light dependent phase called ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose .
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what is nadh made of ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell .
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how many atp are formed in glycolysis and what is the net profit of atp in glycolysis ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen .
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are atp used in pyurate oxidation ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen .
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what are the molecules of atp ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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how many kilo jules of energy is equal to one glucose molecule ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha !
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i have a mitochondrial disorder called mitochondrial encephalopathy lactic acidosis stroke syndrome ( melas ) , my lactic acid levels are high mine is 5.4 when the reference range is 0.5-2.2 , why would my lactic acid levels be that high ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle .
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where does that b vit come from ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again .
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where does most of the atp produced in cellular respiration come from ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before .
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the `` kicking out '' of a phosphate group creates energy , right ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups .
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what is nahd and what does it stand for ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane .
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when hank is describing the electron configuration chain i got lost what exactly is happening and where is the atp being produced ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package .
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how come adp is made from atp ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before .
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did hank mean to say `` equals energy '' instead of `` plus energy '' ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? ''
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wait does n't the kreb cycle happen in the mitochondria matrix ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps .
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explain the meaning of the terms cold-blooded and warm-blooded ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package .
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what is atp made up of ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? ''
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why we do n't make alcohol but make latic acid ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs .
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what type of sugar does yeast use to reproduct ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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how does atp production change if your body uses fatty acids rather than glucose ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 .
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hank is saying that usually 29-30 molecules of atp produced for 1 glucose , but if it was a best scenario it would be 38 atps , so where do the rest atps are going , why there is not always 38 ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before .
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i am unable to understand how energy is extracted from atp ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s .
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whats the difference between nadh and nadph ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released .
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why was creatine phosphate system not covered ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before .
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is atp the only source of energy ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen .
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what are the effects of not having enough atp ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle .
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how did a cell or mitochondria make fad and nad+ ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid .
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what happens to the third phosphate group that gets shot off of atp ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen .
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how can the process create different # s of atp molecules ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages .
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hank said that you need 2 nadh to power cellular respiration , but when your first cellular respiration happens where does the 2 nadh come from ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you .
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how is oxaloacetic acid formed , and why in his diagram at about do the carbons keep coming back ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you .
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are the carbons in the citric acid removed until there is just oxaloacetic acid left ?
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hank : oh , hello there i 'm at the gym . i do n't know why you 're here , but i 'm going to do some push-ups . so you can join me on the floor if you want . now i 'm not doing this just to show off or anything , i 'm actually doing this for science , okay . ( grunts ) you see what happened there ? my arms moved . my shoulders moved . my back and stomach muscles moved . my heart pumped blood to all of those different places . it 's pretty neat , huh ? well , it turns out that how we make and use energy is a lot like sports or other kinds of exercise . it can be hard work and a little bit complicated , but if you do it right , it comes with some tremendous payoffs . but unlike hitting a ball with a stick , it 's so marvelously complicated and awesome that we 're still unraveling the mysteries of how it all works , and it all starts with a marvelous molecule that is one of your best friends , atp . ( energetic music ) today , i 'm talking about the energy and the process our cells and other animals ' cells go through to provide themselves with power . cellular respiration is how we derive energy from the food that we eat , specifically from glucose since most of what we eat ends up as glucose . here 's the chemical formula for one molecule of glucose . in order to turn this glucose into energy , we 're going to need to add some oxygen . six molecules of it , to be exact . through cellular respiration , we 're going to turn that glucose and oxygen into six molecules of co2 , six molecules of water , and some energy that we can use for doing all of our push-ups . so that 's all well and good , but here 's the thing , we ca n't just use that energy to run a marathon or something . first , our bodies have to turn that energy into a really specific form of stored energy called atp or adenosine triphosphate . you 've heard me talk about this before . people often refer to atp as the currency of biological energy . think of it as an american dollar . it 's what you need to do business in the u.s. you ca n't just walk into a best buy with a handful of chinese yuan or indian rupees and expect to be able to buy anything with them even though they technically are money . same goes with energy , in order to be able to use it , our cells need energy to be transferred into adenosine triphosphate to be able to grow , move , create electrical impulses in our nerves and brains , everything . a while back , for instance , we talked about how cells use atp to transport some kinds of materials in and out of its membranes . to jog your memory about that , you can watch that episode right here . now before we see how atp is actually put together , let 's look at how cells can cash in on the energy that 's stashed in there . well , adenosine triphosphate is made up of a nitrogenous base called adenine with a sugar called ribose and three phosphate groups attached to it . now one thing you need to know about these three phosphate groups , is that they are super uncomfortable sitting together in a row like that , like three kids on a bus who hate each other all sharing the same seat . so because the phosphate groups are such terrible company for each other , atp is able to do this nifty trick where it shoots one of the phosphate groups off the end of the seat , creating adp , or adenosine diphosphate , because now , there are just two kids sitting on the bus seat . and this reaction when the third jerk kid is kicked off the seat , energy is released . and since there are a lot of water molecules just floating around nearby , an oh pairing , that 's called a hydroxide , from one of the h2os comes over and takes the place of that third phosphate group , and everybody is much happier . by the way , when you use water to break down a compound like this , it 's called hydrolysis , `` hydro '' from water and `` lysis '' from the greek word `` for separate '' . so now that you know how atp is spent , let 's see how it is minted , nice and new , by cellular respiration . like i said , it all starts with oxygen and glucose . in fact , textbooks make a point of saying that through cellular respiration , one molecule of glucose can yield a bit of heat and 38 molecules of atp . now , it 's worth noting that this number is kind of a best-case scenario . usually it 's more like 29 or 30 atps , but whatever . people are still studying this stuff , so let 's stick with that number , 38 . now , cellular respiration is n't something that just happens all at once . glucose is transformed into atps over three separate stages . glycolysis , the krebs cycle , and the electron transport chain . traditionally , these stages are described as coming one after the other but really everything in the cell , is kind of happening all at the same time . but let 's start with the first step , glycolysis , or the breaking down of the glucose . glucose , of course , is a sugar , you know this because it 's got an `` ose '' at the end of it . and glycolysis is just the breaking up of glucose 's six-carbon ring into two three-carbon molecules called pyruvic acids or pyruvate molecules . now in order to explain how exactly glycolysis works , i 'd need about an hour of your time , and a giant cast of finger puppets each playing a different enzyme , and though it would pain me to do it , i would have to use words like phosphoglucoisomerase , but a simple way of explaining it , is like this , if you wan na make some money , you got ta spend some money . glycolysis needs the investment of two atps in order to work and in the end , it generates four atps , for a net profit if you will of two atps . in addition to those four atps , glycolysis results in two pyruvates and two super energy-rich morsels called nadh , which are sort of the love children of a b vitamin called nad+ pairing with energized electrons and a hydrogen to create storehouses of energy that will later be tapped to make atp . to help us keep track of all the awesome stuff we 're making here , let 's keep score . so far we 've created two molecules of atp and two molecules of nadh , which will be used to power more atp production later . now , a word about oxygen . like i mentioned , oxygen is necessary for the overall process of cellular respiration . but not every stage of it . glycolysis , for example , can take place without oxygen , which makes it an anaerobic process . in the absence of oxygen , the pyruvates formed through glycolysis gets rerouted into a process called fermentation . if there 's no oxygen in the cell , it needs more of that nad+ to keep the glycolysis going . so fermentation frees up some nad+ , which happens to create some interesting byproducts . for instance , in some organisms , like yeasts , the product of fermentation is ethyl alcohol , which is the same thing as all of this lovely stuff . but luckily for our day-to-day productivity , our muscles do n't make alcohol when they do n't get enough oxygen . if that were the case , working out would make us drunk , which actually would be pretty awesome but instead of ethyl alcohol , they make lactic acid . which is what makes you feel sore after that workout that kicked your butt . so , your muscles used up all the oxygen they had and they had to kick into anaerobic respiration in order to get the energy that they needed . and so you have all this lactic acid building up in your muscle tissues . ha ! ah ! ah ! back to the score . now we 've made two molecules of atp through glycolysis , but your cells really need the oxygen in order to make the other 30-some molecules that they need . that 's because the next two stages of cellular respiration , the krebs cycle and the electron transport chain , are both aerobic processes , which means that they require oxygen . and so we find ourselves at the next step in cellular respiration . after glycolysis , comes the krebs cycle . so , while glycolysis occurs in the cytoplasm or the fluid medium within the cell that all the organelles hang out in , the krebs cycle happens across the inner membrane of the mitochondria , which are generally considered the power centers of the cell . the krebs cycle takes the products of glycolysis . those carbon-rich pyruvates and reworks them to create another two atps per glucose molecule , plus some energy and a couple of other forms , which i 'll talk about in a minute . here 's how . first , one of the pyruvates is oxidized , which basically means that it 's combined with oxygen . one of the carbons off the three-carbon chain bonds with an oxygen molecule and leaves the cell as co2 . what 's left is a two-carbon compound called acetyl coenzyme a or acetyl coa . then , another nad+ comes along , picks up a hydrogen and becomes nadh . so our two pyruvates create another two molecules of nadh to be used later . as in glycolysis , and really all life , enzymes are essential here . they are the proteins that bring together the stuff that needs to react with each other , and they bring them together in just the right way . these enzymes , for example , bring together a phosphate with an adp , to create another atp molecule for each pyruvate . enzymes also help join the acetyl coa and a four-carbon molecule called oxaloacetic acid . i think that 's how you pronounce it . together they form a six-carbon molecule called citric acid and i 'm certain that that 's how you pronounce that one because yeah , it 's the stuff that 's in orange juice . ( lively piano music ) fun fact , the krebs cycle is also known as the citric acid cycle because of this very byproduct . however , it is usually referred to by the name of the man who figured it all out . hans krebs , an ear , nose , and throat surgeon who fled nazi germany to teach biochemistry at cambridge , where he discovered this incredibly complex cycle in 1937 . for being such a total freaking genius , he was awarded the nobel prize for medicine in 1953 . anyway , the citric acid is then oxidized over a bunch of intricate steps , cutting carbons off left and right , to eventually get back to oxaloacetic acid , which is what makes the krebs cycle a cycle . and as the carbons get cleaved off the citric acid , there are leftovers in the form of co2 or carbon dioxide , which are exhaled by the cell , and eventually by you . you and i , as we continue our existence as people , are exhaling the products of the krebs cycle right now . good work . ( breathes out loudly ) this video , by the way , i 'm using a lot of atp making it . now , each time a carbon comes off of the citric acid , some energy is made , but it 's not atp . it 's stored in a whole different kind of molecular package . this is where we go back to nad+ and its sort of colleague fad . nad+ and fad are chummy little enzymes that are related to b vitamins . derivatives of niacin and riboflavin , which you might have seen in the vitamin aisle . these b vitamins are good at holding onto high energy electrons and keeping that energy until it can get released later in the electron transport chain . in fact , they 're so good at it , that they show up in a lot of those high-energy vitamin powders that the kids are taking these days . nad+s and fads are like batteries , big awkward batteries that pick up hydrogen and energized electrons from each pyruvate , which in effect charges them up . the addition of hydrogen turns them into nadh and fadh2 , respectively . each pyruvate yields three nadhs and one fadh2 per cycle , and since each glucose has been broken down into two pyruvates that means each glucose molecule can produce six nadhs and two fadh2s . the main purpose of the krebs cycle is to make these powerhouses for the next and final step , the electron transport chain . and now comes the time when your saying , `` sweet pyruvate sandwiches , hank , `` are n't we supposed to be making atp here ? `` let 's make it happen , capt'n ! what 's the holdup ? '' well friends , your patience is finally paying off because when it comes to atps , the electron transport chain is the real moneymaker . in a very efficient cell , it can net a whopping 34 atps . so , remember all those nadhs and fadh2s we made in the krebs cycle ? well , their electrons are going to provide the energy that will work as a pump along a chain of channel proteins across the inner membrane of the mitochondria where the krebs cycle occurred . these proteins will swap these electrons to send hydrogen protons from inside the very center of the mitochondria , across its inner membrane to the outer compartment of the mitochondria . but once they 're out , the protons want to get back to the other side of the inner membrane , because there 's a lot of other protons out there and as we 've learned , nature always tends to seek a nice , peaceful balance on either side of a membrane . so all of these anxious protons are allowed back in through a special protein called atp synthase . and the energy of this proton flow drives this crazy spinning mechanism that squeezes some adp and some phosphates together to form atp . so , the electrons from the 10 nadhs that come out of the krebs cycle , have just enough energy to produce roughly three atps each . and we ca n't forget our friends the fadh2s . we have two of them and they make two atps each . and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again . we made two atps for each pyruvate during glycolysis . we made two during the krebs cycle , and then during the electron transport chain we made about 34 . and that is just for one molecule of glucose . imagine how much your body makes and uses every single day .
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and voila ! that is how animal cells , the world over , make atp through cellular respiration . now just to check , let 's reset our atp counter and do the math for a single glucose molecule once again .
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why is cellular respiration the best way to make atp ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle .
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could someone explain to me how you can have 'o ' as the circumcenter of a triangle it is not in ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius .
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why does sal write that any unique triangle has a unique circumcenter and circumradius ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius .
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i do agree that 3 points define a unique triangle , but different triangles can have the same circumcenter and circumradius , right ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here .
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what are or what is euclid 's elements ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses .
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my question : can one construct a triangle in a bounded circle with a side through 0 that is not a right triangle ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc .
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why is it correct to say `` circumscribed about a triangle '' rather than `` circumscribed around a triangle '' or something else ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here .
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why can you not use the orthocenter of a triangle as the 3 points ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper .
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do you use the circumcenter because you are able to find the circumradius , which would be the radius of the inscribed circle ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses .
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what if we have a obtuse angled triangle ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here .
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do the perpendicular bisectors of the three sides always intersect ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool .
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why do three points determine a circle ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle .
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how did sal get those three red lines ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here .
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in the last video , sal proved that the circumcenter of a right triangle is always on the hypotenuse , but is n't there a way to construct a right triangle on a circle without the hypotenuse going through the center ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here .
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in the last video , sal proved that the circumcenter of a right triangle is always on the hypotenuse , but is n't there a way to construct a right triangle on a circle without the hypotenuse going through the center ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation .
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so if a circumcenter does n't necessarily have to be in the triangle , where is the center of the triangle ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper .
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how do you know how large or small to make the circle ( how many units ) from the circumcenter all the way around ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation .
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is there a difference between the centriod and the circumcenter of a triangle ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review .
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why does sal always call the circumcenter point o ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points .
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how do you find the equation for the circumcircle ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that .
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how do you calculate a center angle ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here .
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is this theorem in euclid 's elements ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation .
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how come the circumcenter of the triangle is n't even in the center ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper .
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why is a circle 360 degrees ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter .
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how would you find the circumcenter of a triangle mathematically ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a .
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what does the perpendicular mean ?
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we know that three points define a triangle . so if i were to take three random points here , so let 's call that point a , point b , and then let 's say this is point c right over here . if we say that these three points are the vertices of a triangle , they define a unique triangle . so this would be triangle a -- try to draw my lines as straight as possible -- triangle abc . now we 've also learned in the last few videos that triangle abc has a unique circumcenter . and that is a point that is equidistant to these three vertices , it equidistant to these three points . so the way can we can find it is we draw a perpendicular bisector of each of these sides and where the three perpendicular bisectors intersect -- and we show that they always intersect at a unique point -- that is that circumcenter . and i 'll do it really quick right over here . so let 's say that this is the perpendicular bisector of that side , this is the perpendicular bisector of that side , and this is the perpendicular bisector of that side . so these are all perpendicular , this is perpendicular , and they each bisect the sides . b to this point is going to be equal to this point to a . a to this point is going to be equal to that point to c. c to this point is going to be equal to that point to b . and this point right over here , we 've already talked about , we 'll call that point o . we call that the circumcenter . o is the circumcenter . this is all a little bit of review . so if you have three points , you have a unique triangle . that unique triangle has a unique circumcenter , which is equidistant to the three points of the triangle , three -- i should say the three vertices of the triangle -- and that distance between the circumcenter and the three points , the three vertices , i should say . so let me draw that in a different color . so this distance , oa , the length of oa , the length of oc , and the length of ob , so oa is equal to oc is equal to ob , which is the c circumradius . and we 've learned when we first talked about circles , if you give me a point , and if we find the locus of all points that are equidistant from that point , then that is a circle . and when i say a locus , all i mean is , the set of all points . if you give me any point right over here , so that 's an arbitrary point , and you also specify a radius , and say what is the set of all the points on this two dimensional plane that are equidistant , that are that radius away from the center ? it uniquely defines a circle . that 's how we defined a circle right over here . and similarly , if you say , look , if you start with the center at o , and you say all of the points that are the circumradius away from o , it will uniquely identify a circle . and that circle will contain the points a , b , and c because those are the circumradius away from o . so they are included in that set . so the circle would look something like -- let me draw it . it would look something like this -- trying my best to draw it , just like that . everything we 've talked about , just now within the last few minutes , is all review . we know all of this . but i went over it just to kind of reinstate a pretty interesting idea , that if you give me three points that defines a unique triangle , and if you have a unique triangle -- and let me make it clear . this is three non-collinear points , so three points not on the same line . if you have three points that are not on the same line , that defines a unique triangle . for any unique triangle you have a unique circumcenter and circumradius . i 'll rewrite it , i do n't want to get lazy and confuse you -- circumradius . and if you give me any point in space , any unique point , and a radius , the set of all points that are exactly that radius away from it , that defines a unique circle . so we went through all of this business of talking about the unique triangle , and the unique circumcenter , and the unique radius , to really just show you that if you give me any three points that eventually , really , just defines a unique circle . so just as you need three points to define a triangle , you also need three points to define a circle , two points wo n't do it . and one way to think about it is , if you give me two points , there 's an infinite number of triangles that i construct with those two points , because i could put the third point anywhere . i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses . and so they 're going to have different circles that circumscribe about those triangles . so this one -- so for example , this would be one circle that could go around , that could circumscribe that triangle . you could have this circle right over here . so you see clearly , very clearly , that two points are not enough . you need three points , three points lead to a triangle , lead to a unique circle . so that by itself is kind of cool . now , another question is , if i have just a circle , and if it 's circumscribed about an arbitrary triangle , is the center of that circle necessarily the circumcenter ? so let 's think about that a little bit , because there are some non-intuitive cases here . so if i draw a circle right over here , its center is right over there . and if i draw an arbitrary triangle where all of the vertices of that triangle are on this circle , is this center necessarily the circumcenter of that triangle ? so let me draw a crazy situation . so let me draw one where this thing is clearly outside of the triangle , so that we could have a triangle that looks like this . and it 's clearly all three vertices sit on the circle . so you might at first say , wait , there 's no way this could be the circumcenter , it 's not even inside the triangle . but remember , this point right here is equidistant to every point on the circle . i should say , every point on this circle is equidistant from this point , they 're all the radius away . and all three points of this triangle are on the circle , so they are all exactly a radius away from this point right over here . so this distance right over here is going to be a radius , this distance right over here is going to be a radius , and this distance right over here is going to be a radius . now , this point is clearly equidistant from that point and that point . we know that , it 's exactly r away from both of those vertices of the triangle . so if it 's equidistant -- and we proved this in a previous video -- if it 's equidistant from both of those points , it must be on the perpendicular bisector of the segment that joins those two points . so this must be on the perpendicular bisector -- so that 's perpendicular and it bisects that segment right over there . but we can make the same argument for this segment right over here , because this point is r from the center -- we 'll call it o , i am tired of just saying this point . point o is equidistant from -- let me label these , so let 's call this a , b , c. so we already said point o is equidistant from c and b , so it must be on the perpendicular bisector of bc . and it 's also equidistant from a and b . it 's r away from both , because a and b both sit on the circle , they 're both a radius away from the center . so it also must sit on the perpendicular bisector of ab . let me draw it a little bit neater , there you go . so it must also be on this perpendicular bisector . and then finally , it also is equidistant from a . it 's for the same distance from a is it is from c. because those are both r away , they both sit on the circle , so it must be on the perpendicular bisector of ac as well . so ac is right over here . this is what the interesting thing is , we 're seeing that the three perpendicular bisectors of the three sides of this triangle , they do definitely intersect , but they are intersecting at a point outside of that triangle . and that point is the center of the circle . so once again , the last idea is , o is equidistant from a and c , so it must sit on the perpendicular bisector of ac , which would look something like this , which would look something like that . so once again , we see the three perpendicular bisectors are intersecting at a unique point , and o really is the circumcenter . so if you take any circle , if you take a circle , and if you put any triangle whose vertices sit on the circle , the center of that circle is its circumcenter . so we just drew a situation where this is the circumcenter that sits outside of the triangle proper . so point o is also going to be the circumcenter of this triangle right over here . and point o is also going to be the circumcenter of this triangle right over here . it 's going to sit on all three perpendicular bisectors of this , and we know that because it 's equidistant from all three points of any of these triangles where the vertices sit on the circle itself .
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i could construct this triangle . i could construct this triangle , i could construct this triangle , i can construct this triangle . and all of these triangles are going to have different circumcenters and different radiuses .
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can o be in the middle of the triangle ?
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welcome to the presentation on averages . averages is probably a concept that you 've already used before , maybe not in a mathematical way . but people will talk in terms of , the average voter wants a politician to do this , or the average student in a class wants to get out early . so you 're probably already familiar with the concept of an average . and you probably already intuitively knew that an average is just a number that represents the different values that a group could have . but it can represent that as one number as opposed to giving all the different values . and let 's give a couple of examples of how to compute an average , and you might already know how to do this . so let 's say i had the numbers 1 , 3 , 5 , and 20 . and i asked you , what is the average of these four numbers ? well , what we do is , we literally just add up the numbers . and then divide by the number of numbers we have . so we say 1 plus 3 is 4 . so let me write that . 1 plus 3 plus 5 plus 20 equals , let 's see , 1 plus 3 is 4 . 4 plus 5 is 9 . 9 plus 20 is 29 . and we had 4 numbers ; one , two , three , four . so 4 goes into 29 . and it goes , 7 , 7 , 28 . and then we have 10 , i did n't have to do that decimal there , oh well . 2 , 8 , 25 . so 4 goes into 29 7.25 times . so the average of these four numbers is equal to 7.25 . and that might make sense to you because 7.25 is someplace in between these numbers . and we can kind of view this , 7.25 , as one way to represent these four numbers without having to list these four numbers . there are other representations you 'll learn later on . like the mode . you 'll also the mean , which we 'll talk about later , is actually the same thing as the average . but the average is just one number that you can use to represent a set of numbers . so let 's do some problems which i think are going to be close to your heart . let 's say on the first four tests of an exam , i got a -- let 's see , i got an 80 , an 81 . an 87 , and an 88 . what 's my average in the class so far ? well , all i have to do is add up these four numbers . so i say , 80 plus 81 plus 87 plus 88 . well , zero plus 1 is 1 . 1 plus 7 is 8 . 8 plus 8 is 16 . i just ran eight miles , so i 'm a bit tired . and , 4/8 , so that 's 32 . plus 1 is 33 . and now we divide this number by 4 . 4 goes into 336 . goes into 33 , 8 times . 8 times 4 is 32 . 33 minus 32 is 1 , 16 . 4 . so the average is equal to 84 . so depending on what school you go to that 's either a b or a c. so , so far my average after the first four exams is an 84 . now let 's make this a little bit more difficult . we know that the average after four exams , at four exams , is equal to 84 . if i were to ask you what do i have to get on the next test to average an 88 , to average an 88 in the class . so let 's say that x is what i get on the next test . so now what we can say is , is that the first four exams , i could either list out the first four exams that i took . or i already know what the average is . so i know the sum of the first four exams is going to 4 times 84 . and now i want to add the , what i get on the 5th exam , x . and i 'm going to divide that by all five exams . so in other words , this number is the average of my first five exams . we just figured out the average of the first four exams . but now , we sum up the first four exams here . we add what i got on the fifth exam , and then we divide it by 5 , because now we 're averaging five exams . and i said that i need to get in an 88 in the class . and now we solve for x . let me make some space here . so , 5 times 88 is , let 's see . 5 times 80 is 400 , so it 's 440 . 440 equals 4 times 84 , we just saw that , is 320 plus 16 is 336 . 336 plus x is equal to 440 . well , it turns out if you subtract 336 from both sides , you get x is equal to 104 . so unless you have a exam that has some bonus problems on it , it 's probably impossible for you to get ah an 88 average in the class after just the next exam . you 'd have to get 104 on that next exam . and let 's just look at what we just did . we said , after 4 exams we had an 84 . what do i have to get on that next exam to average an 88 in the class after 5 exams ? and that 's what we solved for when we got x . now , let 's ask another question . i said after four exams , after four exams , i had an 84 average . if i said that there are 6 exams in the class , and the highest score i could get on an exam is 100 , what is the highest average i can finish in the class if i were to really study hard and get 100 on the next 2 exams ? well , once again , what we 'll want to do is assume we get 100 on the next 2 exams and then take the average . so we 'll have to solve all 6 exams . so we 're going to have the average of 6 , so in the denominator we 're going to have 6 . the first four exams , the sum , as we already learned , is 4 exams times the 84 average . and this dot is just times . plus , and there 's going to be 2 more exams , right ? because there 's 6 exams in the class . and i 'm going to get 100 in each . so that 's 200 . and what 's this average ? well , 4 times 84 , we already said , is 336 . plus 200 over 6 . so that 's 536 over 6 . 6 goes into 5 36 . i do n't know if if i gave myself enough space . but 6 goes into 53 , 8 times . 48 . 56 . 9 times . 9 times 6 is 54 . 6 minus is 20 6 goes into -- so we 'll see it 's actually 89.333333 , goes on forever . so 89.3 repeating . so no matter how hard i try in this class , the best i can do . because i only have two exams left , even if i were to get 100 on the next two exams . i can finish the class with an 89.333 average . hopefully , i think some of this might have been a little bit of a review for you . you already had kind of a sense of what an average is . and hopefully these last two problems not only taught you how to do some algebra problems involving average , but they 'll also help you figure out how well you have to do on your exams to get an a in your math class . i think you 're now ready for the average module . have fun .
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and then divide by the number of numbers we have . so we say 1 plus 3 is 4 . so let me write that .
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1+3+7=11 , but ( assuming since sal averages four numbers , he puts 4 here , i did 3 , so i put 3 ) how would i write down the fourth three that goes into 11 ?
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welcome to the presentation on averages . averages is probably a concept that you 've already used before , maybe not in a mathematical way . but people will talk in terms of , the average voter wants a politician to do this , or the average student in a class wants to get out early . so you 're probably already familiar with the concept of an average . and you probably already intuitively knew that an average is just a number that represents the different values that a group could have . but it can represent that as one number as opposed to giving all the different values . and let 's give a couple of examples of how to compute an average , and you might already know how to do this . so let 's say i had the numbers 1 , 3 , 5 , and 20 . and i asked you , what is the average of these four numbers ? well , what we do is , we literally just add up the numbers . and then divide by the number of numbers we have . so we say 1 plus 3 is 4 . so let me write that . 1 plus 3 plus 5 plus 20 equals , let 's see , 1 plus 3 is 4 . 4 plus 5 is 9 . 9 plus 20 is 29 . and we had 4 numbers ; one , two , three , four . so 4 goes into 29 . and it goes , 7 , 7 , 28 . and then we have 10 , i did n't have to do that decimal there , oh well . 2 , 8 , 25 . so 4 goes into 29 7.25 times . so the average of these four numbers is equal to 7.25 . and that might make sense to you because 7.25 is someplace in between these numbers . and we can kind of view this , 7.25 , as one way to represent these four numbers without having to list these four numbers . there are other representations you 'll learn later on . like the mode . you 'll also the mean , which we 'll talk about later , is actually the same thing as the average . but the average is just one number that you can use to represent a set of numbers . so let 's do some problems which i think are going to be close to your heart . let 's say on the first four tests of an exam , i got a -- let 's see , i got an 80 , an 81 . an 87 , and an 88 . what 's my average in the class so far ? well , all i have to do is add up these four numbers . so i say , 80 plus 81 plus 87 plus 88 . well , zero plus 1 is 1 . 1 plus 7 is 8 . 8 plus 8 is 16 . i just ran eight miles , so i 'm a bit tired . and , 4/8 , so that 's 32 . plus 1 is 33 . and now we divide this number by 4 . 4 goes into 336 . goes into 33 , 8 times . 8 times 4 is 32 . 33 minus 32 is 1 , 16 . 4 . so the average is equal to 84 . so depending on what school you go to that 's either a b or a c. so , so far my average after the first four exams is an 84 . now let 's make this a little bit more difficult . we know that the average after four exams , at four exams , is equal to 84 . if i were to ask you what do i have to get on the next test to average an 88 , to average an 88 in the class . so let 's say that x is what i get on the next test . so now what we can say is , is that the first four exams , i could either list out the first four exams that i took . or i already know what the average is . so i know the sum of the first four exams is going to 4 times 84 . and now i want to add the , what i get on the 5th exam , x . and i 'm going to divide that by all five exams . so in other words , this number is the average of my first five exams . we just figured out the average of the first four exams . but now , we sum up the first four exams here . we add what i got on the fifth exam , and then we divide it by 5 , because now we 're averaging five exams . and i said that i need to get in an 88 in the class . and now we solve for x . let me make some space here . so , 5 times 88 is , let 's see . 5 times 80 is 400 , so it 's 440 . 440 equals 4 times 84 , we just saw that , is 320 plus 16 is 336 . 336 plus x is equal to 440 . well , it turns out if you subtract 336 from both sides , you get x is equal to 104 . so unless you have a exam that has some bonus problems on it , it 's probably impossible for you to get ah an 88 average in the class after just the next exam . you 'd have to get 104 on that next exam . and let 's just look at what we just did . we said , after 4 exams we had an 84 . what do i have to get on that next exam to average an 88 in the class after 5 exams ? and that 's what we solved for when we got x . now , let 's ask another question . i said after four exams , after four exams , i had an 84 average . if i said that there are 6 exams in the class , and the highest score i could get on an exam is 100 , what is the highest average i can finish in the class if i were to really study hard and get 100 on the next 2 exams ? well , once again , what we 'll want to do is assume we get 100 on the next 2 exams and then take the average . so we 'll have to solve all 6 exams . so we 're going to have the average of 6 , so in the denominator we 're going to have 6 . the first four exams , the sum , as we already learned , is 4 exams times the 84 average . and this dot is just times . plus , and there 's going to be 2 more exams , right ? because there 's 6 exams in the class . and i 'm going to get 100 in each . so that 's 200 . and what 's this average ? well , 4 times 84 , we already said , is 336 . plus 200 over 6 . so that 's 536 over 6 . 6 goes into 5 36 . i do n't know if if i gave myself enough space . but 6 goes into 53 , 8 times . 48 . 56 . 9 times . 9 times 6 is 54 . 6 minus is 20 6 goes into -- so we 'll see it 's actually 89.333333 , goes on forever . so 89.3 repeating . so no matter how hard i try in this class , the best i can do . because i only have two exams left , even if i were to get 100 on the next two exams . i can finish the class with an 89.333 average . hopefully , i think some of this might have been a little bit of a review for you . you already had kind of a sense of what an average is . and hopefully these last two problems not only taught you how to do some algebra problems involving average , but they 'll also help you figure out how well you have to do on your exams to get an a in your math class . i think you 're now ready for the average module . have fun .
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33 minus 32 is 1 , 16 . 4 . so the average is equal to 84 .
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so you just add all the numbers together and then divide by how ever many numbers there are so like 2+4+6+8=20 then divide 20/4=5 so 5 would be the average of 2,4,6,8 right ?
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welcome to the presentation on averages . averages is probably a concept that you 've already used before , maybe not in a mathematical way . but people will talk in terms of , the average voter wants a politician to do this , or the average student in a class wants to get out early . so you 're probably already familiar with the concept of an average . and you probably already intuitively knew that an average is just a number that represents the different values that a group could have . but it can represent that as one number as opposed to giving all the different values . and let 's give a couple of examples of how to compute an average , and you might already know how to do this . so let 's say i had the numbers 1 , 3 , 5 , and 20 . and i asked you , what is the average of these four numbers ? well , what we do is , we literally just add up the numbers . and then divide by the number of numbers we have . so we say 1 plus 3 is 4 . so let me write that . 1 plus 3 plus 5 plus 20 equals , let 's see , 1 plus 3 is 4 . 4 plus 5 is 9 . 9 plus 20 is 29 . and we had 4 numbers ; one , two , three , four . so 4 goes into 29 . and it goes , 7 , 7 , 28 . and then we have 10 , i did n't have to do that decimal there , oh well . 2 , 8 , 25 . so 4 goes into 29 7.25 times . so the average of these four numbers is equal to 7.25 . and that might make sense to you because 7.25 is someplace in between these numbers . and we can kind of view this , 7.25 , as one way to represent these four numbers without having to list these four numbers . there are other representations you 'll learn later on . like the mode . you 'll also the mean , which we 'll talk about later , is actually the same thing as the average . but the average is just one number that you can use to represent a set of numbers . so let 's do some problems which i think are going to be close to your heart . let 's say on the first four tests of an exam , i got a -- let 's see , i got an 80 , an 81 . an 87 , and an 88 . what 's my average in the class so far ? well , all i have to do is add up these four numbers . so i say , 80 plus 81 plus 87 plus 88 . well , zero plus 1 is 1 . 1 plus 7 is 8 . 8 plus 8 is 16 . i just ran eight miles , so i 'm a bit tired . and , 4/8 , so that 's 32 . plus 1 is 33 . and now we divide this number by 4 . 4 goes into 336 . goes into 33 , 8 times . 8 times 4 is 32 . 33 minus 32 is 1 , 16 . 4 . so the average is equal to 84 . so depending on what school you go to that 's either a b or a c. so , so far my average after the first four exams is an 84 . now let 's make this a little bit more difficult . we know that the average after four exams , at four exams , is equal to 84 . if i were to ask you what do i have to get on the next test to average an 88 , to average an 88 in the class . so let 's say that x is what i get on the next test . so now what we can say is , is that the first four exams , i could either list out the first four exams that i took . or i already know what the average is . so i know the sum of the first four exams is going to 4 times 84 . and now i want to add the , what i get on the 5th exam , x . and i 'm going to divide that by all five exams . so in other words , this number is the average of my first five exams . we just figured out the average of the first four exams . but now , we sum up the first four exams here . we add what i got on the fifth exam , and then we divide it by 5 , because now we 're averaging five exams . and i said that i need to get in an 88 in the class . and now we solve for x . let me make some space here . so , 5 times 88 is , let 's see . 5 times 80 is 400 , so it 's 440 . 440 equals 4 times 84 , we just saw that , is 320 plus 16 is 336 . 336 plus x is equal to 440 . well , it turns out if you subtract 336 from both sides , you get x is equal to 104 . so unless you have a exam that has some bonus problems on it , it 's probably impossible for you to get ah an 88 average in the class after just the next exam . you 'd have to get 104 on that next exam . and let 's just look at what we just did . we said , after 4 exams we had an 84 . what do i have to get on that next exam to average an 88 in the class after 5 exams ? and that 's what we solved for when we got x . now , let 's ask another question . i said after four exams , after four exams , i had an 84 average . if i said that there are 6 exams in the class , and the highest score i could get on an exam is 100 , what is the highest average i can finish in the class if i were to really study hard and get 100 on the next 2 exams ? well , once again , what we 'll want to do is assume we get 100 on the next 2 exams and then take the average . so we 'll have to solve all 6 exams . so we 're going to have the average of 6 , so in the denominator we 're going to have 6 . the first four exams , the sum , as we already learned , is 4 exams times the 84 average . and this dot is just times . plus , and there 's going to be 2 more exams , right ? because there 's 6 exams in the class . and i 'm going to get 100 in each . so that 's 200 . and what 's this average ? well , 4 times 84 , we already said , is 336 . plus 200 over 6 . so that 's 536 over 6 . 6 goes into 5 36 . i do n't know if if i gave myself enough space . but 6 goes into 53 , 8 times . 48 . 56 . 9 times . 9 times 6 is 54 . 6 minus is 20 6 goes into -- so we 'll see it 's actually 89.333333 , goes on forever . so 89.3 repeating . so no matter how hard i try in this class , the best i can do . because i only have two exams left , even if i were to get 100 on the next two exams . i can finish the class with an 89.333 average . hopefully , i think some of this might have been a little bit of a review for you . you already had kind of a sense of what an average is . and hopefully these last two problems not only taught you how to do some algebra problems involving average , but they 'll also help you figure out how well you have to do on your exams to get an a in your math class . i think you 're now ready for the average module . have fun .
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33 minus 32 is 1 , 16 . 4 . so the average is equal to 84 .
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why is the , '' 84 '' being multiplied by 4 ?
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welcome to the presentation on averages . averages is probably a concept that you 've already used before , maybe not in a mathematical way . but people will talk in terms of , the average voter wants a politician to do this , or the average student in a class wants to get out early . so you 're probably already familiar with the concept of an average . and you probably already intuitively knew that an average is just a number that represents the different values that a group could have . but it can represent that as one number as opposed to giving all the different values . and let 's give a couple of examples of how to compute an average , and you might already know how to do this . so let 's say i had the numbers 1 , 3 , 5 , and 20 . and i asked you , what is the average of these four numbers ? well , what we do is , we literally just add up the numbers . and then divide by the number of numbers we have . so we say 1 plus 3 is 4 . so let me write that . 1 plus 3 plus 5 plus 20 equals , let 's see , 1 plus 3 is 4 . 4 plus 5 is 9 . 9 plus 20 is 29 . and we had 4 numbers ; one , two , three , four . so 4 goes into 29 . and it goes , 7 , 7 , 28 . and then we have 10 , i did n't have to do that decimal there , oh well . 2 , 8 , 25 . so 4 goes into 29 7.25 times . so the average of these four numbers is equal to 7.25 . and that might make sense to you because 7.25 is someplace in between these numbers . and we can kind of view this , 7.25 , as one way to represent these four numbers without having to list these four numbers . there are other representations you 'll learn later on . like the mode . you 'll also the mean , which we 'll talk about later , is actually the same thing as the average . but the average is just one number that you can use to represent a set of numbers . so let 's do some problems which i think are going to be close to your heart . let 's say on the first four tests of an exam , i got a -- let 's see , i got an 80 , an 81 . an 87 , and an 88 . what 's my average in the class so far ? well , all i have to do is add up these four numbers . so i say , 80 plus 81 plus 87 plus 88 . well , zero plus 1 is 1 . 1 plus 7 is 8 . 8 plus 8 is 16 . i just ran eight miles , so i 'm a bit tired . and , 4/8 , so that 's 32 . plus 1 is 33 . and now we divide this number by 4 . 4 goes into 336 . goes into 33 , 8 times . 8 times 4 is 32 . 33 minus 32 is 1 , 16 . 4 . so the average is equal to 84 . so depending on what school you go to that 's either a b or a c. so , so far my average after the first four exams is an 84 . now let 's make this a little bit more difficult . we know that the average after four exams , at four exams , is equal to 84 . if i were to ask you what do i have to get on the next test to average an 88 , to average an 88 in the class . so let 's say that x is what i get on the next test . so now what we can say is , is that the first four exams , i could either list out the first four exams that i took . or i already know what the average is . so i know the sum of the first four exams is going to 4 times 84 . and now i want to add the , what i get on the 5th exam , x . and i 'm going to divide that by all five exams . so in other words , this number is the average of my first five exams . we just figured out the average of the first four exams . but now , we sum up the first four exams here . we add what i got on the fifth exam , and then we divide it by 5 , because now we 're averaging five exams . and i said that i need to get in an 88 in the class . and now we solve for x . let me make some space here . so , 5 times 88 is , let 's see . 5 times 80 is 400 , so it 's 440 . 440 equals 4 times 84 , we just saw that , is 320 plus 16 is 336 . 336 plus x is equal to 440 . well , it turns out if you subtract 336 from both sides , you get x is equal to 104 . so unless you have a exam that has some bonus problems on it , it 's probably impossible for you to get ah an 88 average in the class after just the next exam . you 'd have to get 104 on that next exam . and let 's just look at what we just did . we said , after 4 exams we had an 84 . what do i have to get on that next exam to average an 88 in the class after 5 exams ? and that 's what we solved for when we got x . now , let 's ask another question . i said after four exams , after four exams , i had an 84 average . if i said that there are 6 exams in the class , and the highest score i could get on an exam is 100 , what is the highest average i can finish in the class if i were to really study hard and get 100 on the next 2 exams ? well , once again , what we 'll want to do is assume we get 100 on the next 2 exams and then take the average . so we 'll have to solve all 6 exams . so we 're going to have the average of 6 , so in the denominator we 're going to have 6 . the first four exams , the sum , as we already learned , is 4 exams times the 84 average . and this dot is just times . plus , and there 's going to be 2 more exams , right ? because there 's 6 exams in the class . and i 'm going to get 100 in each . so that 's 200 . and what 's this average ? well , 4 times 84 , we already said , is 336 . plus 200 over 6 . so that 's 536 over 6 . 6 goes into 5 36 . i do n't know if if i gave myself enough space . but 6 goes into 53 , 8 times . 48 . 56 . 9 times . 9 times 6 is 54 . 6 minus is 20 6 goes into -- so we 'll see it 's actually 89.333333 , goes on forever . so 89.3 repeating . so no matter how hard i try in this class , the best i can do . because i only have two exams left , even if i were to get 100 on the next two exams . i can finish the class with an 89.333 average . hopefully , i think some of this might have been a little bit of a review for you . you already had kind of a sense of what an average is . and hopefully these last two problems not only taught you how to do some algebra problems involving average , but they 'll also help you figure out how well you have to do on your exams to get an a in your math class . i think you 're now ready for the average module . have fun .
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and then we have 10 , i did n't have to do that decimal there , oh well . 2 , 8 , 25 . so 4 goes into 29 7.25 times .
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where did the .25 come from ?
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welcome to the presentation on averages . averages is probably a concept that you 've already used before , maybe not in a mathematical way . but people will talk in terms of , the average voter wants a politician to do this , or the average student in a class wants to get out early . so you 're probably already familiar with the concept of an average . and you probably already intuitively knew that an average is just a number that represents the different values that a group could have . but it can represent that as one number as opposed to giving all the different values . and let 's give a couple of examples of how to compute an average , and you might already know how to do this . so let 's say i had the numbers 1 , 3 , 5 , and 20 . and i asked you , what is the average of these four numbers ? well , what we do is , we literally just add up the numbers . and then divide by the number of numbers we have . so we say 1 plus 3 is 4 . so let me write that . 1 plus 3 plus 5 plus 20 equals , let 's see , 1 plus 3 is 4 . 4 plus 5 is 9 . 9 plus 20 is 29 . and we had 4 numbers ; one , two , three , four . so 4 goes into 29 . and it goes , 7 , 7 , 28 . and then we have 10 , i did n't have to do that decimal there , oh well . 2 , 8 , 25 . so 4 goes into 29 7.25 times . so the average of these four numbers is equal to 7.25 . and that might make sense to you because 7.25 is someplace in between these numbers . and we can kind of view this , 7.25 , as one way to represent these four numbers without having to list these four numbers . there are other representations you 'll learn later on . like the mode . you 'll also the mean , which we 'll talk about later , is actually the same thing as the average . but the average is just one number that you can use to represent a set of numbers . so let 's do some problems which i think are going to be close to your heart . let 's say on the first four tests of an exam , i got a -- let 's see , i got an 80 , an 81 . an 87 , and an 88 . what 's my average in the class so far ? well , all i have to do is add up these four numbers . so i say , 80 plus 81 plus 87 plus 88 . well , zero plus 1 is 1 . 1 plus 7 is 8 . 8 plus 8 is 16 . i just ran eight miles , so i 'm a bit tired . and , 4/8 , so that 's 32 . plus 1 is 33 . and now we divide this number by 4 . 4 goes into 336 . goes into 33 , 8 times . 8 times 4 is 32 . 33 minus 32 is 1 , 16 . 4 . so the average is equal to 84 . so depending on what school you go to that 's either a b or a c. so , so far my average after the first four exams is an 84 . now let 's make this a little bit more difficult . we know that the average after four exams , at four exams , is equal to 84 . if i were to ask you what do i have to get on the next test to average an 88 , to average an 88 in the class . so let 's say that x is what i get on the next test . so now what we can say is , is that the first four exams , i could either list out the first four exams that i took . or i already know what the average is . so i know the sum of the first four exams is going to 4 times 84 . and now i want to add the , what i get on the 5th exam , x . and i 'm going to divide that by all five exams . so in other words , this number is the average of my first five exams . we just figured out the average of the first four exams . but now , we sum up the first four exams here . we add what i got on the fifth exam , and then we divide it by 5 , because now we 're averaging five exams . and i said that i need to get in an 88 in the class . and now we solve for x . let me make some space here . so , 5 times 88 is , let 's see . 5 times 80 is 400 , so it 's 440 . 440 equals 4 times 84 , we just saw that , is 320 plus 16 is 336 . 336 plus x is equal to 440 . well , it turns out if you subtract 336 from both sides , you get x is equal to 104 . so unless you have a exam that has some bonus problems on it , it 's probably impossible for you to get ah an 88 average in the class after just the next exam . you 'd have to get 104 on that next exam . and let 's just look at what we just did . we said , after 4 exams we had an 84 . what do i have to get on that next exam to average an 88 in the class after 5 exams ? and that 's what we solved for when we got x . now , let 's ask another question . i said after four exams , after four exams , i had an 84 average . if i said that there are 6 exams in the class , and the highest score i could get on an exam is 100 , what is the highest average i can finish in the class if i were to really study hard and get 100 on the next 2 exams ? well , once again , what we 'll want to do is assume we get 100 on the next 2 exams and then take the average . so we 'll have to solve all 6 exams . so we 're going to have the average of 6 , so in the denominator we 're going to have 6 . the first four exams , the sum , as we already learned , is 4 exams times the 84 average . and this dot is just times . plus , and there 's going to be 2 more exams , right ? because there 's 6 exams in the class . and i 'm going to get 100 in each . so that 's 200 . and what 's this average ? well , 4 times 84 , we already said , is 336 . plus 200 over 6 . so that 's 536 over 6 . 6 goes into 5 36 . i do n't know if if i gave myself enough space . but 6 goes into 53 , 8 times . 48 . 56 . 9 times . 9 times 6 is 54 . 6 minus is 20 6 goes into -- so we 'll see it 's actually 89.333333 , goes on forever . so 89.3 repeating . so no matter how hard i try in this class , the best i can do . because i only have two exams left , even if i were to get 100 on the next two exams . i can finish the class with an 89.333 average . hopefully , i think some of this might have been a little bit of a review for you . you already had kind of a sense of what an average is . and hopefully these last two problems not only taught you how to do some algebra problems involving average , but they 'll also help you figure out how well you have to do on your exams to get an a in your math class . i think you 're now ready for the average module . have fun .
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33 minus 32 is 1 , 16 . 4 . so the average is equal to 84 .
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can anybody make me understand what has sal said between ?
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