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58 Cards in this Set
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The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction _____. A- gains electrons and loses potential energy B- loses electrons and loses potential energy C- gains electrons and gains potential energy D- loses electrons and gains potential energy |
B- loses electrons and loses potential energy |
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When electrons move closer to a more electronegative atom, what happens? The more electronegative atom is _____. A- and energy is released B- oxidized, and energy is consumed C- oxidized, and energy is released D- reduced, and energy is consumed |
A- and energy is released |
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Which of the listed statements describes the results of the following reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy A- C6H12O6 is oxidized and O2 is reduced. B- O2 is reduced and CO2 is oxidized. C- O2 is oxidized and H2O is reduced. D- CO2 is reduced and O2 is oxidized. |
A- C6H12O6 is oxidized and O2 is reduced. |
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When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes _____. A- reduced B- an oxidizing agent C- oxidized D- hydrolyzed |
C- oxidized |
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Which of the following statements about NAD+ is true? A- NAD+ can donate electrons for use in oxidative phosphorylation. B- NAD+ has more chemical energy than NADH. C- NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. D- In the absence of NAD+, glycolysis can still function. |
C- NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. |
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Carbohydrates and fats are considered high-energy foods because they _____. A- have no nitrogen in their makeup. B- are easily reduced. C- have a lot of oxygen atoms. D- have a lot of electrons associated with hydrogen. |
D- have a lot of electrons associated with hydrogen. |
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A cell has enough available ATP to meet its needs for about 30 seconds. What is likely to happen when an athlete exhausts his or her ATP supply? A- ATP is transported into the cell from the circulatory system. B- He or she has to sit down and rest. C- Catabolic processes are activated that generate more ATP. D- Other cells take over, and the muscle cells that have used up their ATP cease to function. |
C- Catabolic processes are activated that generate more ATP. |
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Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis? A- 2% B- 100% C- 0% D- 38% |
B- 100% |
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Starting with one molecule of glucose, the energy-containing products of glycolysis are _____. A- 2 NADH, 2 pyruvate, and 2 ATP B- 2 NAD+, 2 pyruvate, and 2 ATP C- 2 FADH2, 2 pyruvate, and 4 ATP D- 6 CO2, 2 pyruvate, and 2 ATP |
A- 2 NADH, 2 pyruvate, and 2 ATP |
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In glycolysis, for each molecule of glucose oxidized to pyruvate _____. A- two molecules of ATP are used and six molecules of ATP are produced. B- four molecules of ATP are used and two molecules of ATP are produced. C- two molecules of ATP are used and two molecules of ATP are produced. D- two molecules of ATP are used and four molecules of ATP are produced. |
D- two molecules of ATP are used and four molecules of ATP are produced. |
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Most of the CO2 from the catabolism of glucose is released during _____. A- electron transport B- the citric acid cycle C- glycolysis D- chemiosmosis |
B- the citric acid cycle |
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Following glycolysis and the citric acid cycle, but before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is in the form of _____. A- acetyl-CoA B- pyruvate C- NADH D- glucose |
C- NADH |
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Which electron carrier(s) function in the citric acid cycle? A- NAD+ only B- the electron transport chain C- NADH and FADH2 D- ADP and ATP |
C- NADH and FADH2 |
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If you were to add one of the eight citric acid cycle intermediates to the culture medium of yeast growing in the laboratory, what do you think would happen to the rates of ATP and carbon dioxide production? A- The rate of ATP production would decrease, but the rate of carbon dioxide production would increase. C- There would be no change in ATP production, but we would observe an increased rate of carbon dioxide production. D- The rates of ATP production and carbon dioxide production would both increase. |
C- There would be no change in ATP production, but we would observe an increased rate of carbon dioxide production. |
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Carbon dioxide (CO2) is released during which of the following stages of cellular respiration? A- fermentation and glycolysis B- oxidation of pyruvate to acetyl CoA and the citric acid cycle C- glycolysis and the oxidation of pyruvate to acetyl CoA D- oxidative phosphorylation and fermentation |
B- oxidation of pyruvate to acetyl CoA and the citric acid cycle |
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If glucose is the sole energy source, what fraction of the carbon dioxide exhaled by animals is generated by the reactions of the citric acid cycle? A- 1/6 B- 1/3 C- 2/3 D- all of it |
C- 2/3 |
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For each mole of glucose (C6H12O6) oxidized by cellular respiration, how many moles of CO2 are released in the citric acid cycle (see the accompanying figure)? A- 32 B- 4 C- 6 D- 2 |
B- 4 |
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If pyruvate oxidation is blocked, what will happen to the levels of oxaloacetate and citric acid in the citric acid cycle shown in the accompanying figure? A- Oxaloacetate will decrease and citric acid will accumulate. B- Both oxaloacetate and citric acid will accumulate C- Both oxaloacetate and citric acid will decrease. D- Oxaloacetate will accumulate and citric acid will decrease. |
D- Oxaloacetate will accumulate and citric acid will decrease. |
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Starting with citrate, which of the following combinations of products would result from three acetyl CoA molecules entering the citric acid cycle (see the accompanying figure)? A- 38 ATP, 6 CO2, 3 NADH, and 12 FADH2 B- 3 ATP, 3 CO2, 3 NADH, and 3 FADH2 C- 3 ATP, 6 CO2, 9 NADH, and 3 FADH2 D- 1 ATP, 2 CO2, 3 NADH, and 1 FADH2 |
C- 3 ATP, 6 CO2, 9 NADH, and 3 FADH2 |
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In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate (1) loses a carbon, which is given off as a molecule of CO2, (2) is oxidized to form a two-carbon compound called acetate, and (3) is bonded to coenzyme A.The three listed steps result in the formation of _____. A- acetyl CoA, NAD+, ATP, and CO2 B- acetyl CoA, NADH, and CO2 C- acetyl CoA, FADH2, and CO2 D- acetyl CoA, O2, and ATP |
B- acetyl CoA, NADH, and CO2 |
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Which one of the following is formed by the removal of a carbon (as CO2) from a molecule of pyruvate? A- citrate B- glyceraldehyde 3-phosphate C- acetyl CoA D- oxaloacetate |
C- acetyl CoA |
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The electron transport chain _____. A- takes place in the cytoplasm of prokaryotic cells B- is driven by ATP consumption C- is a series of redox reactions D- is a series of substitution reactions |
C- is a series of redox reactions |
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During aerobic respiration, electrons travel downhill in which sequence? A- glucose → NADH → electron transport chain oxygen B- glucose → ATP → electron transport chain NADH C- glucose → pyruvate → ATP → oxygen D- food → glycolysis → citric acid cycle → NADH → ATP |
A- glucose → NADH → electron transport chain oxygen |
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Where are the proteins of the electron transport chain located? A- mitochondrial intermembrane space B- mitochondrial inner membrane C- mitochondrial matrix D- mitochondrial outer membrane |
B- mitochondrial inner membrane |
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During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level? A- FADH2 B- ADP + Phosphorus C- ATP D- NADH |
A- FADH2 |
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The primary role of oxygen in cellular respiration is to _____. A- combine with carbon, forming CO2 B- combine with lactate, forming pyruvate C- yield energy in the form of ATP as it is passed down the respiratory chain D- act as an acceptor for electrons and hydrogen, forming water |
D- act as an acceptor for electrons and hydrogen, forming water |
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During aerobic respiration, H2O is formed. Where does the oxygen atom for the formation of the water come from? A- molecular oxygen (O2) B- carbon dioxide (CO2) C- pyruvate (C3H3O3-) D- glucose (C6H12O6) |
A- molecular oxygen (O2) |
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In chemiosmosis, what is the most direct source of energy that is used to convert ADP + Pi (Phosphorus) to ATP? A- energy released from substrate-level phosphorylation B- energy released as electrons flow through the electron transport system C- energy released from movement of protons through ATP synthase, down their electrochemical gradient D- No external source of energy is required because the reaction is exergonic. |
C- energy released from movement of protons through ATP synthase, down their electrochemical gradient |
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Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells? A- mitochondrial intermembrane space B- mitochondrial inner membrane C- mitochondrial matrix D- mitochondrial outer membrane |
A- mitochondrial intermembrane space |
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When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the _____. A- reduction of NAD+ B- formation of ATP C- creation of a proton-motive force D- lowering of pH in the mitochondrial matrix |
C- creation of a proton-motive force |
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Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration? A- 4 B- 2 C- 30-32 D- 18-24 |
C- 30-32 |
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In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve? A- It increases the surface for substrate-level phosphorylation. B- It allows for an increased rate of glycolysis. C- It allows for an increased rate of the citric acid cycle. D- It increases the surface for oxidative phosphorylation. |
D- It increases the surface for oxidative |
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You have a friend who lost 7 kg (about 15 pounds) of fat on a regimen of strict diet and exercise. How did the fat leave his body? A- It was converted to heat and then released. B- It was released as CO2 and H2O. C- It was converted to ATP, which weighs much less than fat. D- It was converted to urine and eliminated from the body. |
B- It was released as CO2 and H2O. |
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Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in _____. A- only eukaryotic cells, in the presence of oxygen B- all cells, but only in the presence of oxygen C- all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors D- only in mitochondria, using either oxygen or other electron acceptors |
C- all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors |
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Which of the following normally occurs regardless of whether or not oxygen (O2) is present? A- fermentation B- oxidative phosphorylation (chemiosmosis) C- citric acid cycle D- glycolysis |
D- glycolysis |
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Which of the following occurs in the cytosol of a eukaryotic cell? A- glycolysis and fermentation B- citric acid cycle C- oxidation of pyruvate to acetyl CoA D- fermentation and chemiosmosis |
A- glycolysis and fermentation |
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In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of _____. A- ATP, pyruvate, and acetyl CoA B- ATP, CO2, and ethanol (ethyl alcohol) C- ATP, NADH, and pyruvate D- ATP, CO2, and lactate |
B- ATP, CO2, and ethanol (ethyl alcohol) |
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One function of both alcohol fermentation and lactic acid fermentation is to _____. A- reduce FAD+ to FADH2 B- oxidize NADH to NAD+ C- reduce NAD+ to NADH D- reduce FADH2 to FAD+ |
B- oxidize NADH to NAD+ |
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An organism is discovered that thrives in both the presence and absence of oxygen in the air. Curiously, the consumption of sugar increases as oxygen is removed from the organism's environment, even though the organism does not gain much weight. This organism _____. A- is photosynthetic B- is a facultative anaerobe C- is an anaerobic organism D- is a normal eukaryotic organism |
B- is a facultative anaerobe |
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Why is glycolysis considered to be one of the first metabolic pathways to have evolved? A- It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms. B- It produces much less ATP than does oxidative phosphorylation. C- It is found in prokaryotic cells but not in eukaryotic cells. D- It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells. |
A- It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms. |
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New biosensors, applied like a temporary tattoo to the skin, can alert serious athletes that they are about to "hit the wall" and find it difficult to continue exercising. These biosensors monitor lactate, a form of lactic acid, released in sweat during strenuous exercise. Which of the statements below is the best explanation of why athletes would need to monitor lactate levels? B- During aerobic respiration, muscles cells produce too much lactate which causes a rise in the pH of the muscle cells, thus athletes must consume increased amounts of sports drinks, high in electrolytes, to buffer the pH. C- During anaerobic respiration, muscle cells receive too little oxygen and begin to convert lactate to pyruvate (pyruvic acid), thus athletes experience cramping and fatigue. D- During aerobic respiration, muscle cells cannot produce enough lactate to fuel muscle cell contractions and muscles begin to cramp, thus athletic performance suffers. |
A- During anaerobic respiration, lactate levels increase when muscles cells need more energy, however muscles cells eventually fatigue, thus athletes should modify their activities to increase aerobic respiration. |
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What is the oxidizing agent in the following reaction? Pyruvate + NADH + H+ → Lactate + NAD+ A- lactate B- NAD+ C- pyruvate D- NADH |
C- pyruvate |
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High levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in glycolysis. Citric acid binds to the enzyme at a different location from the active site. This is an example of _____. A- the specificity of enzymes for their substrates B- competitive inhibition C- allosteric regulation D- positive feedback regulation |
C- allosteric regulation |
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Glycolysis is active when cellular energy levels are _____; the regulatory enzyme, phosphofructokinase, is _____ by ATP. A- low; activated B- high; activated C- high; inhibited D- low; inhibited |
D- low; inhibited |
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A young dog has never had much energy. He is brought to a veterinarian for help and she decides to conduct several diagnostic tests. She discovers that the dog's mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of the dog's condition? A- His cells cannot move NADH from glycolysis into the mitochondria. B- His cells lack the enzyme in glycolysis that forms pyruvate. C- His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane. D- His cells have a defective electron transport chain, so glucose goes to lactate instead of to acetyl CoA. |
C- His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane. |
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In respiration, beta oxidation involves the _____. A- oxidation of glucose B- oxidation of pyruvate C- regulation of glycolysis D- breakdown of fatty acids |
D- breakdown of fatty acids |
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Fatty acids usually have an even number of carbons in their structures. They are catabolized by a process called beta-oxidation. The end products of the metabolic pathway are acetyl groups of acetyl CoA molecules. These acetyl groups _____. A- directly enter the citric acid cycle B- directly enter the electron transport chain C- directly enter the energy-yielding stages of glycolysis D- are directly decarboxylated by pyruvate dehydrogenase |
A- directly enter the citric acid cycle |
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Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? A- the citric acid cycle B- synthesis of acetyl CoA from pyruvate C- reduction of pyruvate to lactate D- glycolysis E- the electron transport chain |
D- glycolysis |
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The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is A- water. B- pyruvate. C- oxygen. D- ADP. E- NAD+. |
C- oxygen. |
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What is the oxidizing agent in the following reaction? Pyruvate + NADH + H+ → Lactate + NAD+ A- NAD+ B- NADH C- oxygen D- pyruvate E- lactate |
D- pyruvate |
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When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? A- The pH of the matrix increases. B- The cytochromes phosphorylate ADP to form ATP. C- ATP synthase pumps protons by active transport. D- The electrons gain free energy. E- NAD+ is oxidized. |
A- The pH of the matrix increases. |
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Most CO2 from catabolism is released during A- glycolysis. B- electron transport. C- lactate fermentation. D- the citric acid cycle. E- oxidative phosphorylation. |
D- the citric acid cycle. |
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In the combined processes of glycolysis and cellular respiration, what is consumed and what is produced? A- Oxygen is consumed, and glucose is produced. B- Water is consumed, and ATP is produced. C- Oxygen is consumed, and glucose is produced.Water is consumed, and ATP is produced.Carbon dioxide is consumed, and water is produced. D- ATP is consumed, and oxygen is produced. E- Glucose is consumed, and carbon dioxide is produced. |
E- Glucose is consumed, and carbon dioxide is produced. |
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A glucose molecule is completely broken down to carbon dioxide and water in glycolysis and the citric acid cycle, but together these two processes yield only a few molecules of ATP. What happened to most of the energy that the cell obtains from the oxidation of glucose? A- It is stored in the carbon dioxide and water molecules released by these processes. B- It is stored in NADH and FADH2 C- It is stored in pyruvate. D- It is stored in the ATP that was formed by glycolysis and the citric acid cycle. E- It was lost as heat. |
B- It is stored in NADH and FADH2 |
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The electrons stripped from glucose in cellular respiration end up in which compound? A- carbon dioxide B- oxygen C- NADH D- ATP E- water |
E- water |
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Which of the following statements about the chemiosmotic synthesis of ATP is correct? A- The energy for production of ATP from ADP comes directly from a gradient of electrons across the inner mitochondrial membrane. B- Oxygen participates directly in the reaction that makes ATP from ADP and P. C- The chemiosmotic synthesis of ATP requires that the electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane. D- The chemiosmotic synthesis of ATP occurs only in eukaryotic cells, because it occurs in mitochondria. E- Chemiosmotic ATP synthesis requires oxygen. |
C- The chemiosmotic synthesis of ATP requires that the electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane. (Chemiosmosis uses the energy of a proton gradient to make ATP; the proton gradient is formed by coupling the energy produced by electron transport with movement of protons across the membrane.) |
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Which one of the following statements about the redox reactions of the electron transport chain is correct? A- The oxidation of NADH is directly coupled to the reduction of oxygen to water. B- The redox reactions of the electron transport chain are directly coupled to the movement of protons across a membrane. C- The redox reactions of the electron transport chain are directly coupled with the synthesis of ATP. D- The electron transport chain takes electrons from water and gives them to oxygen. E- NADH gains electrons in the initial reaction of the electron transport chain. |
B- The redox reactions of the electron transport chain are directly coupled to the movement of protons across a membrane. |
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In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?
B- two ATP C- up to 30 ATP D- none, because in the absence of oxygen, no ATP can be made E- none, because all of the available energy remains in either lactate or ethanol |
B- two ATP |
