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section, you will be able to: • How do electrochemical gradients affect the active transport of ions and molecules across membranes? Connection for AP® Courses If a substance must move into the cell against its concentration gradient, the cell must use free energy, often provided by ATP, and carrier proteins acting as... |
10][APLO 2.17][APLO 1.2][APLO 3.24] Active transport mechanisms require the use of the cell’s energy, usually in the form of adenosine triphosphate (ATP). If a substance must move into the cell against its concentration gradient—that is, if the concentration of the substance inside the cell is greater than its concentr... |
. Moving Against a Gradient To move substances against a concentration or electrochemical gradient, the cell must use energy. This energy is harvested from ATP generated through the cell’s metabolism. Active transport mechanisms, collectively called pumps, work against electrochemical gradients. Small substances consta... |
. An antiporter also carries two different molecules or ions, but in different directions. (credit: modification of work by “Lupask”/Wikimedia Commons) 216 Chapter 5 | Structure and Function of Plasma Membranes The primary active transport that functions with the active transport of sodium and potassium allows secondar... |
two ions of potassium move in. This results in the interior being slightly more negative relative to the exterior. This difference in charge is important to creating the conditions necessary for the secondary process. Therefore, the sodium-potassium pump is an electrogenic pump (a pump that creates a charge imbalance)... |
). Many amino acids, as well as glucose, enter a cell this way. This secondary process is also used to store high-energy hydrogen ions in the mitochondria of plant and animal cells for the production of ATP. The potential energy that accumulates in the stored hydrogen ions is translated into kinetic energy as the ions ... |
membrane (e.g., hormones and their target cells) before under going endocytosis. Some human diseases, such as familial hypercholesterolemia, are caused by the failure of receptor-mediated endocytosis. Exocytosis is the process of exporting This OpenStax book is available for free at http://cnx.org/content/col12078/1.6... |
representations or models to describe nonspecific immune defenses in plants and animals. In addition to moving small ions and molecules through the membrane, cells also need to remove and take in larger molecules and particles (see Table 5.2 for examples). Some cells are even capable of engulfing entire unicellular mi... |
. Activity Create a representation/diagram to describe how a neutrophil, a type of human white blood cell, attacks and destroys an invading bacterium. What cellular organelles are involved in this process? Pinocytosis A variation of endocytosis is called pinocytosis. This literally means “cell drinking” and was named a... |
the cytoplasmic side of the plasma membrane. If uptake of a compound is dependent on receptor-mediated endocytosis and the process is ineffective, the material will not be removed from the tissue fluids or blood. Instead, it will stay in those fluids and increase in concentration. Some human diseases are caused by the... |
on the exterior of the cell, and the waste material is expelled into the extracellular space (Figure 5.23). Other examples of cells releasing molecules via exocytosis include the secretion of proteins of the extracellular matrix and secretion of neurotransmitters into the synaptic cleft by synaptic vesicles. Figure 5.... |
ic pump pump that creates a charge imbalance endocytosis type of active transport that moves substances, including fluids and particles, into a cell exocytosis process of passing bulk material out of a cell facilitated transport process by which material moves down a concentration gradient (from high to low concentrati... |
transport active transport that moves ions or small molecules across a membrane and may create a difference in charge across that membrane pump active transport mechanism that works against electrochemical gradients receptor-mediated endocytosis variation of endocytosis that involves the use of specific binding protei... |
so on. This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 5 | Structure and Function of Plasma Membranes 227 In living systems, diffusion of substances into and out of cells is mediated by the plasma membrane. Some materials diffuse readily through the membrane, but others are hind... |
tosis imports substances that the cell needs from the extracellular fluid. The cell expels waste in a similar but reverse manner: it pushes a membranous vacuole to the plasma membrane, allowing the vacuole to fuse with the membrane and incorporate itself into the membrane structure, releasing its contents to the exteri... |
asked about organisms that live in fresh water? a. Will their bodies take in too much water? b. Can they control their tonicity? c. Can they survive in salt water? d. Will their bodies lose too much water to their d. preventing high temperatures from increasing environment? fluidity of membranes 7. Identify the princi... |
free at http://cnx.org/content/col12078/1.6 Chapter 5 | Structure and Function of Plasma Membranes 229 a. b. c. d. It transports only small amounts of fluid. It does not involve the pinching off of membrane. It brings in only a specifically targeted substance. It brings substances into the cell, while phagocytosis rem... |
the polar fatty acid tails face towards water. d. Phospholipids are hydrophilic molecules. The polar head faces towards water and the nonpolar fatty acid tails face towards other fatty acid tails. 19. Why is it advantageous for the plasma membrane to be fluid in nature? a. Fluidity allows greater flexibility to the ce... |
Temperature does not affect the rate of diffusion. Density is inversely proportional to molecular movement. Greater distance speeds up the diffusion. d. Larger molecules move slower than lighter molecules. Increasing or decreasing temperature increases or decreases the energy in the medium, affecting molecular movemen... |
the opsonization of the receptor and its ligand in caveolae-coated vesicles. d. Endocytosis involves the opsonization of the receptor and its ligand in clathrin-coated vesicles. In exocytosis, waste material is enveloped in a membrane that fuses with the exterior of the plasma membrane via attachment proteins. TEST PR... |
ic poisoning disrupts the Na+ / Cl− pump, leading to decreased transport of Cl− ions outside the epithelial cells. This increases the electrolyte concentration in the mucus and movement of water out of the cells. The mucus becomes hydrated as in CF. c. Arsenic poisoning affects the oxidative phosphorylation pathway, le... |
cium. c. The rate of contraction would increase with decreasing osmolarity because more salt diffuses into the Paramecium. d. The rate of contraction would decrease with decreasing osmolarity because more salt diffuses into the Paramecium. The sodium-potassium (Na+ / K+ ) pump functions like an anti-porter transporting... |
as its transportation remains unaffected by the presence of ouabain. The binding of K+ occurs on the inner surface of the cell, as its transportation is blocked when ouabain is present inside the cell b. The binding of K+ occurs on the outer surface of the cell, as its transportation is blocked when ouabain is present... |
b. Opsonins are proteins that enhance phagocytosis, whereas clathrin opposes phagocytosis. c. Opsonin stabilizes the inward facing surface of the plasma membrane, which engulfs the antigen, whereas clathrin marks the antigen for phagocytosis by neutrophils. d. Opsonin marks the antigen for phagocytosis by neutrophils,... |
of water across a cell membrane are gated. Both low and high pH within a plant cell can cause alterations of the membranespanning protein. Describe the advantage of this feedback mechanism. Predict how conditions of flooding or drought could activate this mechanism. 41. Rice plants grown in high-salt environments can ... |
bird needs energy to maintain prolonged periods of flight. The bird obtains its energy from taking in food and transforming the nutrients into energy through a series of biochemical reactions. The flight muscles in birds are extremely efficient in energy production. (credit: modification of work by Cory Zanker) Chapter... |
have now discovered a way to replace the missing enzyme in the brain of mice. Read more about the scientists’ research here (http://openstaxcollege.org/l/32mpsiiib). 6.1 | Energy and Metabolism In this section, you will explore the following questions: • What are metabolic pathways? • What are the differences between ... |
the concept of common ancestry for all organisms. Essential Knowledge 1.B.1 Organisms share many conserved core processes and features that evolved and are widely distributed among organisms today. Science Practice Learning Objective 6.1 The student can justify claims with evidence. 1.16 The student is able to justify... |
metabolism of sugar (a simple carbohydrate) is a classic example of the many cellular processes that use and produce energy. Living things consume sugar as a major energy source, because sugar molecules have a great deal of energy stored within their bonds. The breakdown of glucose, a simple sugar, is described by the... |
inside the sugar molecules. The harvested energy is used to make high-energy ATP molecules, which can be used to perform work, powering many chemical reactions in the cell. The amount of energy needed to make one molecule of glucose from six molecules of carbon dioxide is 18 molecules of ATP and 12 molecules of NADPH ... |
ukaryotes perform catabolic processes without oxygen (fermentation); that is, they perform or use anaerobic metabolism. Organisms probably evolved anaerobic metabolism to survive (living organisms came into existence about 3.8 billion years ago, when the atmosphere lacked oxygen). Despite the differences between organi... |
is important to know that the chemical reactions of metabolic pathways don’t take place spontaneously. Each reaction step is facilitated, or catalyzed, by a protein called an enzyme. Enzymes are important for catalyzing all types of biological reactions—those that require energy as well as those that release energy. F... |
free energy. The ΔG of a reaction can be negative or positive, depending on whether the reaction releases energy (exergonic) or requires energy input (endergonic). All reactions require an input of energy called activation energy in order to reach the transition state at which they will proceed. (In another section, w... |
world. Types of Energy When an object is in motion, there is energy associated with that object. In the example of an airplane in flight, there is a great deal of energy associated with the motion of the airplane. This is because moving objects are capable of enacting a change, or doing work. Think of a wrecking ball.... |
the ground has potential energy if it is compressed; so does a rubber band that is pulled taut. The very existence of living cells relies heavily on structural potential energy. On a chemical level, the bonds that hold the atoms of molecules together have potential energy. Remember that anabolic cellular pathways requ... |
energy associated with chemical reactions quantified and expressed? How can the energy released from 246 Chapter 6 | Metabolism one reaction be compared to that of another reaction? A measurement of free energy is used to quantitate these energy transfers. Free energy is called Gibbs free energy (abbreviated with the ... |
G and consequently release free energy are called exergonic reactions. Think: exergonic means energy is exiting the system. These reactions are also referred to as spontaneous reactions, because they can occur without the addition of energy into the system. Understanding which chemical reactions are spontaneous and rel... |
b: modification of work by USDA; credit c: modification of work by “Athlex”/Flickr; credit d: modification of work by Harry Malsch) 248 Chapter 6 | Metabolism Look at each of the processes shown, and decide if it is endergonic or exergonic. In each case, does enthalpy increase or decrease, and does entropy increase or... |
x.org/content/col12078/1.6 Chapter 6 | Metabolism 249 be added, removed, or changed. If a cell were a closed system, its chemical reactions would reach equilibrium, and it would die because there would be insufficient free energy left to perform the work needed to maintain life. In a living cell, chemical reactions are... |
at a lower or higher energy state than both the reactants and the products. However, regardless of this measure, the transition state of the reaction exists at a higher energy state than the reactants, and thus, EA is always positive. 250 Chapter 6 | Metabolism Watch an animation of energy_reaction) site. the move fro... |
cellular temperatures alone provided enough heat energy for these exergonic reactions to overcome their activation barriers, the essential components of a cell would disintegrate. This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 6 | Metabolism 251 Figure 6.10 Activation energy is... |
higher energy state than the reactants, and so 252 Chapter 6 | Metabolism these are nonspontaneous reactions. However, all reactions (including spontaneous –∆G reactions) require an initial input of energy in order to reach the transition state, at which they’ll proceed. This initial input of energy is called the acti... |
, reproduction and maintenance of living systems require free energy and matter. 2.A.1 All living systems require constant input of free energy. 6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices. 2.1 The student is able to explain how biological systems use ... |
stoves transform chemical energy from natural gas into heat energy. Plants perform one of the most biologically useful energy transformations on earth: that of converting the energy of sunlight into the chemical energy stored within organic molecules, as shown in Figure 6.2. Some examples of energy transformations are... |
heat energy helps to maintain our body temperature. Strictly speaking, no energy transfer is completely efficient, because some energy is lost in an unusable form. An important concept in physical systems is that of order and disorder (also known as randomness). The more energy that is lost by a system to its surround... |
that aren’t useful energy sources. This process increases the entropy of the system’s surroundings. Since all energy transfers result in the loss of some usable energy, the second law of thermodynamics states that every energy transfer or transformation increases the entropy of the universe. Even though living things ... |
Adenosine Triphosphate In this section, you will explore the following questions: • Why is ATP considered the energy currency of the cell? • How is energy released through the hydrolysis of ATP? 256 Chapter 6 | Metabolism Connection for AP® Courses Adenosine triphosphate or ATP is the energy “currency” or carrier of t... |
test questions for this section that will help you prepare for the AP exam. These questions address the following standards: [APLO 2.2][APLO 4.14][APLO 2.7][APLO 2.35] Even exergonic, energy-releasing reactions require a small amount of activation energy in order to proceed. However, consider endergonic reactions, whi... |
ATP and a water molecule. Because this reaction takes place with the use of a water molecule, it is considered a hydrolysis reaction. In other words, ATP is hydrolyzed into ADP in the following reaction: ATP + H2 O → ADP + Pi + free energy Like most chemical reactions, the hydrolysis of ATP to ADP is reversible. The r... |
ions and importing two K+ ions), one molecule of ATP must be hydrolyzed. When ATP is hydrolyzed, its gamma phosphate doesn’t simply float away, but is actually transferred onto the pump protein. This process of a phosphate group binding to a molecule is called phosphorylation. As with most cases of ATP hydrolysis, a p... |
onic reaction of ATP hydrolysis is coupled with the endergonic reaction of converting glucose into a phosphorylated intermediate in the pathway. Once again, the energy released by breaking a phosphate bond within ATP was used for the phosphorylation of another molecule, creating an unstable intermediate and powering an... |
cells occur spontaneously, but happen too slowly to meet the needs of a cell. For example, a teaspoon of sucrose (table sugar), a disaccharide, in a glass of iced tea will take time to break down into two monosaccharides, glucose and fructose; however, if you add a small amount of the enzyme sucrase to the tea, sucros... |
a transparent foundation for the AP® Biology course, an inquiry-based laboratory experience, instructional activities, and AP® Exam questions. A Learning Objective merges required content with one or more of the seven science practices. Big Idea 4 Enduring Understanding 4.B Biological systems interact, and these syste... |
two products. The location within the enzyme where the substrate binds is called the enzyme’s active site. The active site is where the “action” happens, so to speak. Since enzymes are proteins, there is a unique combination of amino acid residues (also called side chains, or R groups) within the active site. Each res... |
(Figure 6.16). The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes a mild shift in the enzyme’s structure that confirms an ideal binding arrangement between the enzyme and th... |
molecules as a necessary step of the reaction process. In these cases, it is important to remember that the enzyme will always return to its original state at the completion of the reaction. One of the hallmark properties of enzymes is that they remain ultimately unchanged by the reactions they catalyze. After an enzy... |
, an inhibitor molecule is similar enough to a substrate that it can bind to the active site and simply block the substrate from binding. When this happens, the enzyme is inhibited through competitive inhibition, because an inhibitor molecule competes with the substrate for active site binding (Figure 6.17). On the oth... |
of the enzyme HMG-CoA reductase. HMG-CoA reductase is the enzyme that synthesizes cholesterol from lipids in the body. By inhibiting this enzyme, the levels of cholesterol synthesized in the body can be reduced. Similarly, acetaminophen is an inhibitor of the enzyme cyclooxygenase. While it is effective in providing r... |
ism hydrogen, which are required for enzyme action. The most common sources of coenzymes are dietary vitamins (Figure 6.20). Some vitamins are precursors to coenzymes and others act directly as coenzymes. Vitamin C is a coenzyme for multiple enzymes that take part in building the important connective tissue component, ... |
of enzyme activity. Feedback inhibition involves the use of a reaction product to regulate its own further production (Figure 6.21). The cell responds to the abundance of specific products by slowing down production during anabolic or catabolic reactions. Such reaction products may inhibit the enzymes that catalyzed t... |
at a given time, the desired reactions are being catalyzed and the undesired reactions are not. Enzymes are regulated by cellular conditions, such as temperature and pH. They are also regulated through their location within a cell, sometimes being compartmentalized so that they can only catalyze reactions under certai... |
that is not work (energy of the motion of molecules or particles) heat energy total bond energy of reactants or products in a chemical reaction induced fit dynamic fit between the enzyme and its substrate, in which both components modify their structures to allow for ideal binding kinetic energy type of energy associa... |
ergonic reaction. One with a positive ∆G that requires energy input is called an endergonic reaction. Exergonic reactions are said to be spontaneous, because their products have less energy than their reactants. The products of endergonic reactions have a higher energy state than the reactants, and so these are nonspon... |
ergonic reaction. 6.5 Enzymes Enzymes are chemical catalysts that accelerate chemical reactions at physiological temperatures by lowering their activation energy. Enzymes are usually proteins consisting of one or more polypeptide chains. Enzymes have an active site that provides a unique chemical environment, made up o... |
unwinding two strands of parent DNA, copying each strand to synthesize complementary strands and releasing the resulting two semi-conserved strands of DNA. Which of the following accurately describes this process? a. This is an anabolic process. b. This is a catabolic process. a. glucose b. protein c. d. triglycerides... |
between the two reactions. b. Compare their reaction rates. c. Compare their ideal environmental conditions. d. Compare the spontaneity between the two reactions. 12. Which of the terms in the Gibbs free energy equation denotes enthalpy? a. ΔG b. ΔH c. ΔS d. ΔT 13. Which chemical reaction is more likely to occur? a. d... |
the effect of inputting energy into a living system? a. b. c. It decreases entropy within the system. It fuels catabolic reactions. It causes enthalpy. substrate c. binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate d. binds directly ... |
to release energy for use in chemical reactions? a. b. c. d. the adenosine molecule the bond between the first and second phosphates the bond between the first phosphate and the adenosine molecule the bond between the second and third phosphates This OpenStax book is available for free at http://cnx.org/content/col120... |
molecules. These ATP molecules transfer energy from one reaction to other. d. Energy is released in the form of water from the breakdown of glucose. These molecules transfer energy from one reaction to other. 32. Name two different cellular functions that require energy. a. Phagocytosis helps amoebae take up nutrients... |
farm is in the state of higher entropy before the earthquake and energy is given out of the system after the earthquake. d. The ant farm is in the state of lower entropy before the earthquake and energy is given out of the system after the earthquake. 37. Energy transfers take place constantly in every day activities.... |
level of entropy refers to higher state of symmetry in the system and it can be reduced by release of energy to lower the entropy. c. Higher level of entropy refers to low disorder in the system and it can be reduced by input of energy to increase the entropy. d. Higher level of entropy refers to higher state of disor... |
TEST PREP FOR AP® COURSES 46. Cell metabolism is a complex process that uses many types of chemicals in a variety of processes. Which of the following statements is true? 43. If a chemical reaction could occur without an enzyme, why is it important to have one? a. Enzymes are important because they give the desired pr... |
down through aerobic respiration, a number of ATP can be made from the energy extracted. How many ATP are possible? a. 2 to 4 b. 36 to 38 c. 10 to 12 d. 24 to 30 53. Plants must have adequate resources to complete their functions. If they do not have what they need, there are changes in the organism’s metabolism. What... |
be expressed as the number of energy containing molecules used to make one molecule of glucose. Which of the following best states the number of each molecule needed? a. 54 molecules of ATP and 18 molecules of nicotinamide adenine dinucleotide phosphate (NADPH) b. 18 molecules of ATP and 12 molecules of NADPH c. 24 mo... |
can be stored in a sugar bowl by creating a diagram similar to Figure 6.10. 3. 4. 5. If table sugar is placed in a spoon held over a high flame, the sugar is charred and becomes a blackened mixture composed primarily of carbon. Create a visual representation that includes a chemical equation to explain the role of the... |
scales characteristic of living systems on Earth—that is to say, life as we know it. The time scale required for half of the molecules of initial sucrose to remain can be estimated. The relationship between the half-life and the activation energy is: t1 / 2 = 0.69×10 E A / 2.3RT At a temperature of 300K, approximately... |
and after boiling. Predict the effect of the energy transfer on the entropy of the system, and justify your prediction. 5. [Extension/Connection] Molecules of water have simple responses to heating: The molecules move faster and interact less strongly with other neighboring molecules. Consider the primary producers of... |
. Consequently, vegan diets in developing nations and diets common to developing nations provide no source of B12. Researchers (Ghosh et al. http://dx.doi.org/10.3389/fnut.2016.00001]) found that rats whose diets contained limited (L) and no (N) B12 displayed symptoms that were not observed in the control group (C) who... |
engers that regulate metabolism and blood vessel production and dilation. High concentrations of adipocytokines are commonly found among individuals with abnormal autoimmune response. Monocyte chemoattractant protein 1 (MCP-1) is involved in the trafficking or guiding of monocytes to damaged tissue, as in a wound. In m... |
one form and is converted into another form that can fuel the organism’s life functions. In the process of photosynthesis, plants and other photosynthetic producers take in energy in the form of light (solar energy) and convert it into chemical energy, glucose, which stores this energy in its chemical bonds. Then, a s... |
concepts and Learning Objectives outlined in Big Idea 2 and Big Idea 4 of the AP® Biology Curriculum Framework, as shown in the table. The Learning Objectives listed in the Curriculum Framework provide a transparent foundation for the AP® Biology course, an inquiry-based laboratory experience, instructional activities... |
Rather, the electron is shifted to a second compound, reducing the second compound. The shift of an electron from one compound to another removes some potential energy from the first compound (the oxidized compound) and increases the potential energy of the second compound (the reduced compound). The transfer of elect... |
and photosynthesis. Figure 7.2 The oxidized form of the electron carrier (NAD+) is shown on the left and the reduced form (NADH) is shown on the right. The nitrogenous base in NADH has one more hydrogen ion and two more electrons than in NAD+. 284 Chapter 7 | Cellular Respiration ATP in Living Systems A living cell ca... |
phosphate group to a molecule requires energy. Phosphate groups are negatively charged and thus repel one another when they are arranged in series, as they are in ADP and ATP. This repulsion makes the ADP and ATP molecules inherently unstable. The release of one or two phosphate groups from ATP, a process called depho... |
�A − enzyme − ∼ P⎤ ⎦ → B + enzyme + ADP + phosphate ion When the intermediate complex breaks apart, the energy is used to modify the substrate and convert it into a product of the reaction. The ADP molecule and a free phosphate ion are released into the medium and are available for recycling through cell metabolism. Su... |
but not the other steps of respiration. Symptoms of mitochondrial diseases can include muscle weakness, lack of coordination, stroke-like episodes, and loss of vision and hearing. Most affected people are diagnosed in childhood, although there are some adult-onset diseases. Identifying and treating mitochondrial disor... |
ultimately produced. High-energy electrons and hydrogen atoms pass to NAD+, reducing it to NADH. Although two molecules of ATP were invested to destabilize glucose at the beginning of the process, four molecules of ATP are formed by substrate-level phosphorylation, resulting in a net gain of two ATP and two NADH molec... |
The student can construct explanations of phenomena based on evidence produced through scientific practices. 2.5 The student is able to construct explanations of the mechanisms and structural features of cells that allow organisms to capture, store, or use free energy. You have read that nearly all of the energy used ... |
ate. An isomerase is an enzyme that catalyzes the conversion of a molecule into one of its isomers. (This change from phosphoglucose to phosphofructose allows the eventual split of the sugar into two three-carbon molecules.). Step 3. The third step is the phosphorylation of fructose-6-phosphate, catalyzed by the enzyme... |
7.7) oxidizes the sugar (glyceraldehyde-3-phosphate), extracting high-energy electrons, which are picked up by the electron carrier NAD+, producing NADH. The sugar is then phosphorylated by the addition of a second phosphate group, producing 1,3-bisphosphoglycerate. Note that the second phosphate group does not requir... |
produces phosphoenolpyruvate (PEP). Step 10. The last step in glycolysis is catalyzed by the enzyme pyruvate kinase (the enzyme in this case is named for the reverse reaction of pyruvate’s conversion into PEP) and results in the production of a second ATP molecule by substratelevel phosphorylation and the compound pyr... |
respiration—the process in which organisms convert energy in the presence of oxygen—and glycolysis is their sole source of ATP. If glycolysis is interrupted, these cells lose their ability to maintain their sodium-potassium pumps, and eventually, they die. The last step in glycolysis will not occur if pyruvate kinase,... |
” Because matter and energy cannot be created or destroyed, we must account for everything.) The electrons are picked up by NAD+, and NADH carries the electrons to a later pathway (the electron transport chain described below) for ATP production. The glucose molecule that originally entered cellular respiration in glyc... |
and quantitatively. 4.6 The student is able to use representations and models to analyze situations qualitatively to describe how interactions of subcellular structures, which possess specialized functions, provide essential functions. The Science Practice Challenge Questions contain additional test questions for this... |
CoA, producing a molecule of acetyl CoA. Figure 7.9 Upon entering the mitochondrial matrix, a multi-enzyme complex converts pyruvate into acetyl CoA. In the process, carbon dioxide is released and one molecule of NADH is formed. Note that during the second stage of glucose metabolism, whenever a carbon atom is removed... |
, the acetyl group from acetyl CoA is attached to a four-carbon oxaloacetate molecule to form a six-carbon citrate molecule. Through a series of steps, citrate is oxidized, releasing two carbon dioxide molecules for each acetyl group fed into the cycle. In the process, three NAD+ molecules are reduced to NADH, one FAD ... |
OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 7 | Cellular Respiration 295 is regulated by feedback inhibition of ATP, succinyl CoA, and NADH. Step 5. In step five, a phosphate group is substituted for coenzyme A, and a high-energy bond is formed. This energy is used in substrate-l... |
Two carbon atoms come into the citric acid cycle from each acetyl group, representing four out of the six carbons of one glucose molecule. Two carbon dioxide molecules are released on each turn of the cycle; however, these do not necessarily contain the most recently added carbon atoms. The two acetyl carbon atoms wil... |
the AP® Biology Curriculum Framework, as shown in the table. As shown in the table, concepts covered in this section also align to the Learning Objectives listed in the Curriculum Framework that provide a transparent foundation for the AP® Biology course, an inquiry-based laboratory experience, instructional activitie... |
P, producing ATP. Electron Transport Chain The electron transport chain (Figure 7.11) is the last component of aerobic respiration and is the only part of glucose metabolism that uses atmospheric oxygen. Oxygen continuously diffuses into plants; in animals, it enters the body through the respiratory system. Electron tr... |
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