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let g of x equal cosine of x . so let 's actually graph that . so that would be the graph right over there . i drew it ahead of time . so this is a segment of cosine of x between x is equal to 0 and x equals pi . obviously , it keeps on going in both directions after that . and then they ask us , what is the limit as h...
obviously , it keeps on going in both directions after that . and then they ask us , what is the limit as h approaches 0 of g of pi plus h minus g of pi over h ? so let 's just think about it a little bit .
i was able to simplify* the equation to the limit as h -- > 0 of 1-cos ( h ) -- -- -- -- h any advice on how to proceed from here ?
let g of x equal cosine of x . so let 's actually graph that . so that would be the graph right over there . i drew it ahead of time . so this is a segment of cosine of x between x is equal to 0 and x equals pi . obviously , it keeps on going in both directions after that . and then they ask us , what is the limit as h...
this point is going to go further and further and further to the left . so pi plus h , as h approaches 0 , is going to approach pi . if we assumed h was a negative value , then we would be approaching from here .
how is the limit as h approaches 0 another 0 instead of undefined ?
let g of x equal cosine of x . so let 's actually graph that . so that would be the graph right over there . i drew it ahead of time . so this is a segment of cosine of x between x is equal to 0 and x equals pi . obviously , it keeps on going in both directions after that . and then they ask us , what is the limit as h...
but what is going to happen as h becomes smaller and smaller and smaller ? well , the point pi plus h , g of pi plus h is going to get closer and closer to this point . and the slope of those secant lines -- i know it 's hard to see , because it 's small here -- they 're going to start getting closer and closer to the ...
what is the point of knowing the slop of the equation ?
let g of x equal cosine of x . so let 's actually graph that . so that would be the graph right over there . i drew it ahead of time . so this is a segment of cosine of x between x is equal to 0 and x equals pi . obviously , it keeps on going in both directions after that . and then they ask us , what is the limit as h...
well , what does that look like ? well the slope of the tangent line , we 're at a minimum point at x equals pi right over here . cosine of pi we know is a negative 1 .
can we always assume that the limit equation has not been simplified and represents a point-slope form ?
let g of x equal cosine of x . so let 's actually graph that . so that would be the graph right over there . i drew it ahead of time . so this is a segment of cosine of x between x is equal to 0 and x equals pi . obviously , it keeps on going in both directions after that . and then they ask us , what is the limit as h...
so let 's actually graph that . so that would be the graph right over there . i drew it ahead of time .
how would i know that i need to use sin , cos , or tan and which is appropriate ?
let g of x equal cosine of x . so let 's actually graph that . so that would be the graph right over there . i drew it ahead of time . so this is a segment of cosine of x between x is equal to 0 and x equals pi . obviously , it keeps on going in both directions after that . and then they ask us , what is the limit as h...
so this is just my previous answer divided by 0.1 . so i get 0.04 . now let me make h even smaller .
how did sal get zero for as the limit ?
let g of x equal cosine of x . so let 's actually graph that . so that would be the graph right over there . i drew it ahead of time . so this is a segment of cosine of x between x is equal to 0 and x equals pi . obviously , it keeps on going in both directions after that . and then they ask us , what is the limit as h...
this point is going to go further and further and further to the left . so pi plus h , as h approaches 0 , is going to approach pi . if we assumed h was a negative value , then we would be approaching from here .
there was an expression that mentioned the limit of h- > 0 , and i was wondering -- if h was 0 , then the whole expression would be infinity , and not undefined , right ?
let g of x equal cosine of x . so let 's actually graph that . so that would be the graph right over there . i drew it ahead of time . so this is a segment of cosine of x between x is equal to 0 and x equals pi . obviously , it keeps on going in both directions after that . and then they ask us , what is the limit as h...
i drew it ahead of time . so this is a segment of cosine of x between x is equal to 0 and x equals pi . obviously , it keeps on going in both directions after that .
so if the slope is equal to 0 here , the function of this slope at x=pi is written y=-1 ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
is n't the immune cell supposed to get rid of the viruses , not make more ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i do n't want to offend the chemists and the physicists out there . i actually find those quite fascinating as well . but we 're going to answer , or attempt to start to answer , some of the most fundamental questions of our existence .
how does cell division actually create new cells from just splitting ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
you know , this right here is a molecule of dna . how do we start with things like that , and we get the complexity of living things ? and you might be saying , well , what makes something living ?
but virus do n't have cell structures and virus are living things ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and perhaps most importantly , dna and its role in reproduction and containing information . and we 're going to study cells , which are the basic building block of life . and as we 'll see , even though we view cells as these super , super small , small things , cells in and of themselves are incredibly complex . and ...
how do cells come from other cells ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
how do they do this ? you know , we look around us . how do we , you know , eat a muffin ?
does anyone know what the spleen does in the human body ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i 'm talking about bacteria . and it really is fascinating . how do we start off with inanimate molecules and atoms ?
are we really `` alive '' if we are made up of inanimate material ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
are tympanum and ear drum same ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
you know , this right here is a molecule of dna . how do we start with things like that , and we get the complexity of living things ? and you might be saying , well , what makes something living ?
how did living things come to life ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
how do the hiv viruses emerge from the immune cells ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i 'm talking about plants . i 'm talking about bacteria . and it really is fascinating .
life began with bacteria , then , is the life evolving still from bacteria to complex-structured human ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
what is the purpose of bio- engineering ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
what happens when a lysosome burst inside the cell and all its enzymes are released in the cytoplasm ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
how do we start with things like that , and we get the complexity of living things ? and you might be saying , well , what makes something living ? well , living things convert energy from one form to another .
what exactly makes up a virus ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
why can not we hear sound more than 20000 hz ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and we will study that as we look at evolution and natural selection . so welcome to khan academy 's biology section . i think you 're going to find it fascinating .
what do you mean when you assert that biology is `` based '' ... .. on mathematics ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
they definitely reproduce , and they definitely evolve . but they do n't necessarily have a metabolism . we 'll learn a lot more about that .
is n't mathematics simply a tool ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
or are you claiming that mathematical entities have an ontological status ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
they use that energy to change . and i guess growth is a form of change . they use that energy to reproduce .
is growth a result of metabolism in organisms ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and we will study that as we look at evolution and natural selection . so welcome to khan academy 's biology section . i think you 're going to find it fascinating .
why is mathematics a part of biology ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
they use that energy to grow . they use that energy to change . and i guess growth is a form of change .
what does sal mean by change ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and then perhaps one of the biggest questions of all is how did life come about ? and we will study that as we look at evolution and natural selection . so welcome to khan academy 's biology section . i think you 're going to find it fascinating .
what is the importance of biology with evolution ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
they use that energy to change . and i guess growth is a form of change . they use that energy to reproduce .
what is the full form of dna ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about plants .
why did animals adapt to land ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
they use that energy to change . and i guess growth is a form of change . they use that energy to reproduce .
what is the full form of dna ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i 'm talking about bacteria . and it really is fascinating . how do we start off with inanimate molecules and atoms ?
how does dna and rna really work ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
and how is rna replicated ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and you might be saying , well , what makes something living ? well , living things convert energy from one form to another . they use that energy to grow .
how do we convert energy from one place to another ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals .
is it true that there are 23 chromosomes in the human body ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
what does hiv stand for ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
what does a hiv virus do to your body ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
how do we start off with inanimate molecules and atoms ? you know , this right here is a molecule of dna . how do we start with things like that , and we get the complexity of living things ?
what does dna stand for ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i do n't want to offend the chemists and the physicists out there . i actually find those quite fascinating as well . but we 're going to answer , or attempt to start to answer , some of the most fundamental questions of our existence .
is it actually true that we share 50 % of our dna with the banana ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
even with the bacteria that you can only even see at a microscopic level . in fact , we have so much bacteria as part of what makes us , us . so these are fascinating questions .
how much curve are on roots in the ground of trees ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
why is a double helix called a double helix ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
so even though you imagine cells as these very , very small microscopic things , this incredible complexity . even viruses . viruses are one of these fascinating things that kind of are right on the edge between life and nonlife .
is viruses even consider living or nonliving cause i always hear mixed opinions and their based on having a nucleus or something like that ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
so even though you imagine cells as these very , very small microscopic things , this incredible complexity . even viruses . viruses are one of these fascinating things that kind of are right on the edge between life and nonlife .
can someone explain in depth about the way viruses work ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
how big can a single cell become ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
how do we start off with inanimate molecules and atoms ? you know , this right here is a molecule of dna . how do we start with things like that , and we get the complexity of living things ?
what does dna stand for ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
pm , how do germs infect your body ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
is your dna in every cell in your body ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life .
how can biology be the study of life if life has no physical charecteristics ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
you know , this right here is a molecule of dna . how do we start with things like that , and we get the complexity of living things ? and you might be saying , well , what makes something living ?
would n't biology be the study of living things ( organisms ) ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
how do we start off with inanimate molecules and atoms ? you know , this right here is a molecule of dna . how do we start with things like that , and we get the complexity of living things ?
dna can be changed among differente species ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
you know , this right here is a molecule of dna . how do we start with things like that , and we get the complexity of living things ? and you might be saying , well , what makes something living ? well , living things convert energy from one form to another . they use that energy to grow .
how can a virus be non-living and living at the same time ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
what two taxonomic domains are divided based on the presence , or absence , of peptidoglycan ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings .
is metabolism a really fundamental qualification for classifying which is life and which is not ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
are there any differences between a cell and a virus besides metabolism ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i 'm talking about plants . i 'm talking about bacteria . and it really is fascinating .
is bacteria found in insects ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and so over the course of what you see in biology on khan academy , we 're going to answer these fundamental , fascinating questions . we 're going to think about things like energy and the role of energy in life . we 're going to thing about important molecules in biology .
do all life forms need energy ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and so over the course of what you see in biology on khan academy , we 're going to answer these fundamental , fascinating questions . we 're going to think about things like energy and the role of energy in life . we 're going to thing about important molecules in biology .
what does biology have in energy ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
how do we start off with inanimate molecules and atoms ? you know , this right here is a molecule of dna . how do we start with things like that , and we get the complexity of living things ?
if combine the rna of a virus and the dna of a human , what will we get ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
how do they do this ? you know , we look around us . how do we , you know , eat a muffin ?
do anyone know how to memorize the difference between meiosis and mitosis ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
how big is our diaphragm ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and you might be saying , well , what makes something living ? well , living things convert energy from one form to another . they use that energy to grow .
what types of energy do humans convert ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
which is the longest cell in our body ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i do n't want to offend the chemists and the physicists out there . i actually find those quite fascinating as well . but we 're going to answer , or attempt to start to answer , some of the most fundamental questions of our existence .
how does cell division actually create new cells from just splitting ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
what is the tough membrane that encloses the heart ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and perhaps most importantly , dna and its role in reproduction and containing information . and we 're going to study cells , which are the basic building block of life . and as we 'll see , even though we view cells as these super , super small , small things , cells in and of themselves are incredibly complex .
what is the study of death cells ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
what is speciation in different environments ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
you know , this right here is a molecule of dna . how do we start with things like that , and we get the complexity of living things ? and you might be saying , well , what makes something living ? well , living things convert energy from one form to another . they use that energy to grow .
is a virus living or non-living ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and as we 'll see , even though we view cells as these super , super small , small things , cells in and of themselves are incredibly complex . and if you compare them to an atomic scale , they 're quite large . in fact , this entire blue background that i have there , that 's the surface of an immune cell .
also is there a smaller scale than the atomic scale ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and perhaps most importantly , dna and its role in reproduction and containing information . and we 're going to study cells , which are the basic building block of life . and as we 'll see , even though we view cells as these super , super small , small things , cells in and of themselves are incredibly complex . and ...
what are the cells made of if we are made of cells ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
so these are fascinating questions . how did life even emerge ? and so over the course of what you see in biology on khan academy , we 're going to answer these fundamental , fascinating questions .
what makes life difficult to handle ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
what was the cambrian explosion ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about plants .
but why is it considered in the group of protozoa which comes under animals ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
well , living things convert energy from one form to another . they use that energy to grow . they use that energy to change .
according to the comments , a living thing is classified as something that has the ability to grow , reproduce , take in and use energy , excrete waste and respond to the environment , but what type of waste is produced by plants , and how was this decided by scientists to be considered the truth ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
we 're going to thing about important molecules in biology . and perhaps most importantly , dna and its role in reproduction and containing information . and we 're going to study cells , which are the basic building block of life . and as we 'll see , even though we view cells as these super , super small , small thin...
is it possible for dna to make cancer cells ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and as we 'll see , even though we view cells as these super , super small , small things , cells in and of themselves are incredibly complex . and if you compare them to an atomic scale , they 're quite large . in fact , this entire blue background that i have there , that 's the surface of an immune cell .
how does glycogen compare with starch ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and it really is fascinating . how do we start off with inanimate molecules and atoms ? you know , this right here is a molecule of dna .
can we have genetic similarity between inanimate objects like a wooden desk or glass or ice cream ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
so these are fascinating questions . how did life even emerge ? and so over the course of what you see in biology on khan academy , we 're going to answer these fundamental , fascinating questions .
how do muffins have to do with life ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
we 'll learn a lot more about that . they do n't necessarily use energy and growth in the same way that we would associate with life . and then perhaps one of the biggest questions of all is how did life come about ?
based on the definition of life , would n't fire be living , too ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
how do they do this ? you know , we look around us . how do we , you know , eat a muffin ?
is life all around us ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
how are virus facinating ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
we 're going to thing about important molecules in biology . and perhaps most importantly , dna and its role in reproduction and containing information . and we 're going to study cells , which are the basic building block of life . and as we 'll see , even though we view cells as these super , super small , small thin...
what makes up dna cells ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
where did the energy from that muffin come from ? how are we similar to a plant or an insect ? and we are eerily or strangely similar to these things .
is it possible for any mammal in the planet to have a similar gene structure to homo sapiens ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and we will study that as we look at evolution and natural selection . so welcome to khan academy 's biology section . i think you 're going to find it fascinating .
what is the relationship between medicine and biology ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and we will study that as we look at evolution and natural selection . so welcome to khan academy 's biology section . i think you 're going to find it fascinating .
is medicine more importante than biology ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and perhaps most importantly , dna and its role in reproduction and containing information . and we 're going to study cells , which are the basic building block of life . and as we 'll see , even though we view cells as these super , super small , small things , cells in and of themselves are incredibly complex . and ...
how many types of cells are there and what do they do in our body ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
so these are fascinating questions . how did life even emerge ? and so over the course of what you see in biology on khan academy , we 're going to answer these fundamental , fascinating questions .
at about 0 , bacteria is between life and non-life , what would you call non-life ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
in fact , this entire blue background that i have there , that 's the surface of an immune cell . and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell .
if e get heart why cant we see are c2 ceels ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
why from the immune cell was the hiv emerging from that cell ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
so these are fascinating questions . how did life even emerge ? and so over the course of what you see in biology on khan academy , we 're going to answer these fundamental , fascinating questions .
how is virus `` at the edge of life and non-life '' ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
so even though you imagine cells as these very , very small microscopic things , this incredible complexity . even viruses . viruses are one of these fascinating things that kind of are right on the edge between life and nonlife .
is viruses alive or not ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
what does hiv stand for ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and perhaps most importantly , dna and its role in reproduction and containing information . and we 're going to study cells , which are the basic building block of life . and as we 'll see , even though we view cells as these super , super small , small things , cells in and of themselves are incredibly complex . and ...
so everything living is made of cells ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and so over the course of what you see in biology on khan academy , we 're going to answer these fundamental , fascinating questions . we 're going to think about things like energy and the role of energy in life . we 're going to thing about important molecules in biology .
when we eat , how does energy in food ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
is there any known evidence of what started the chain reaction that eventually developed into humans ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
and what you see here emerging from it , these little yellow things . these are hiv viruses , emerging from an immune cell . so even though you imagine cells as these very , very small microscopic things , this incredible complexity .
what was the first thing that developed into a cell ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
how would you know how many egg cells would there be in a human for three days ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life .
what are 3 types of organ systems ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
so these are fascinating questions . how did life even emerge ? and so over the course of what you see in biology on khan academy , we 're going to answer these fundamental , fascinating questions .
how does the life cycle work ?
i would like to welcome you to biology at khan academy . and biology , as you might now , is the study of life . and i ca n't really imagine anything more interesting than the study of life . and when i say `` life , '' i 'm not just talking about us , human beings . i 'm talking about all animals . i 'm talking about...
you know , this right here is a molecule of dna . how do we start with things like that , and we get the complexity of living things ? and you might be saying , well , what makes something living ? well , living things convert energy from one form to another . they use that energy to grow .
why is it difficult to classify some objects as living or nonliving ?