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Test File
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Life: The Science of Biology, Ninth Edition
Sadava • Hillis • Heller • Berenbaum
Chapter 9: Pathways that Harvest Chemical Energy
TEST FILE QUESTIONS
(By Catherine Ueckert)
Multiple Choice
1. Metabolic syndrome is a disorder with several symptoms including obesity. An
experimental drug, Aicar, may aid in treating this disorder. It works by
a. increasing the rate of glucose oxidation.
b. decreasing oxidative phosphorylation from ATP.
c. increasing the breakdown of fat to yield ATP.
d. stimulating production of fast-twitch muscle fibers.
e. converting slow-twitch muscle fibers into fast-twitch muscle fibers.
Answer: c
Textbook Reference: 9.0 Of mice and marathons
Page: 168–169
Bloom’s Category: 2. Understanding
2. Which of the following statements about metabolic pathways is false?
a. The product of one reaction becomes the reactant for the next reaction.
b. They are a series of enzyme-catalyzed reactions.
c. Almost all are anabolic.
d. They are similar in all organisms.
e. Many are compartmentalized in eukaryotes.
Answer: c
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 169
Bloom’s Category: 2. Understanding
3. Which of the following statements about metabolic pathways is true?
a. Complex chemical transformations in the cell occur in a single reaction.
b. Each reaction requires oxygen.
c. In eukaryotes, they occur in the cytoplasm.
d. They vary from organism to organism.
e. Each one is regulated by specific enzymes.
Answer: e
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 169
Bloom’s Category: 2. Understanding
4. When a molecule loses hydrogen atoms (as opposed to hydrogen ions), it becomes
a. reduced.
b. oxidized.
c. redoxed.
d. hydrogenated.
e. hydrolyzed.
Answer: b
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 169
Bloom’s Category: 1. Remembering
5. ATP is
a. a short-term energy-storage compound.
b. the cell’s principal compound for energy transfers.
c. synthesized within mitochondria.
d. the molecule all living cells rely on to do work.
e. All of the above
Answer: e
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
Bloom’s Category: 2. Understanding
6. In the conversion of succinate to fumarate, hydrogen atoms are transferred to FAD.
The conversion of succinate and FAD to fumarate and FADH2 is an example of
a. hydrolysis.
b. an allosteric reaction.
c. a metabolic pathway.
d. an aerobic reaction.
e. a redox reaction.
Answer: e
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
Bloom’s Category: 3. Applying
7. The oxidation of malate to oxaloacetate is coupled to the reduction of NAD+ to NADH
+ H+. NAD+ is a(n)
a. reducing agent.
b. oxidizing agent.
c. vitamin.
d. phosphate ester.
e. phosphorylating agent.
Answer: b
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
Bloom’s Category: 2. Understanding
8. In all cells, glucose metabolism begins with
a. glycolysis.
b. fermentation.
c. pyruvate oxidation.
d. the citric acid cycle.
e. chemosmosis.
Answer: a
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
Bloom’s Category: 1. Remembering
9. When NADH donates two electrons to ubiquinone during respiration, ubiquinone is
a. reduced.
b. oxidized.
c. phosphorylated.
d. aerobic.
e. hydrolyzed.
Answer: a
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
Bloom’s Category: 3. Applying
10. Which of the following processes occurs when oxygen is unavailable?
a. Pyruvate oxidation
b. The citric acid cycle
c. Fermentation
d. An electron transport chain
e. All of the above
Answer: c
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 171
Bloom’s Category: 2. Understanding
11. Which of the following oxidizes other compounds by gaining free energy and
hydrogen atoms and reduces other compounds by giving up free energy and hydrogen
atoms?
a. Vitamins
b. Adenine
c. ATP
d. NAD
e. Riboflavin
Answer: d
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 171
Bloom’s Category: 2. Understanding
12. The function of NAD+ is to
a. cause the release of energy to adjacent cells when energy is needed in aerobic
conditions.
b. hasten the release of energy when the cell has been deprived of oxygen.
c. carry hydrogen atoms and free energy from compounds being oxidized and to give
hydrogen atoms and free energy to compounds being reduced.
d. block the release of energy to adjacent cells.
e. None of the above
Answer: c
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 171
Bloom’s Category: 2. Understanding
13. NAD
a. is a key electron carrier in redox reactions.
b. requires oxygen to function.
c. is found only in prokaryotes.
d. binds with an acetyl group to form acetyl CoA.
e. detoxifies hydrogen peroxide.
Answer: a
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 171
Bloom’s Category: 1. Remembering
14. In the cell, the site of oxygen utilization is the
a. nucleus.
b. chloroplast.
c. endoplasmic reticulum.
d. mitochondrion.
e. cytosol.
Answer: d
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 171–172
Bloom’s Category: 1. Remembering
15. Glycolysis converts glucose into pyruvate, ATP, and NADH. The process requires
a. oxygen, ATP, and a series of reactions.
b. carbon dioxide, 5 enzyme-catalyzed reactions, and glucose to begin the series of
reactions.
c. pyruvic acid, oxygen, and enzymes to oxidize glucose inside the mitochondria
d. the pyruvate dehydrogenase complex to catalyze the reactions.
e. 10 enzyme-catalyzed reactions, each reaction dependent on the products of the
previous reaction to proceed.
Answer: e
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 172
Bloom’s Category: 2. Understanding
16. For glycolysis to continue, all cells require
a. a respiratory chain.
b. oxygen.
c. mitochondria.
d. chloroplasts.
e. NAD+.
Answer: e
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 172
Bloom’s Category: 2. Understanding
17. During the energy-priming portion of glycolysis, the phosphates from ATP molecules
are
a. added to the first and sixth carbons.
b. added to the second and fourth carbons.
c. wasted, as an energy investment.
d. used to make pyruvate.
e. used to make lactate.
Answer: a
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 173
Bloom’s Category: 3. Applying
18. The oxidation of pyruvate to carbon dioxide is called
a. fermentation.
b. the citric acid cycle.
c. glycolysis.
d. oxidative phosphorylation.
e. the respiratory chain.
Answer: b
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 173
Bloom’s Category: 1. Remembering
19. In steps 6 through 10 of glycolysis, the conversion of 1 mole of glyceraldehyde 3phosphate to pyruvate yields 2 moles of ATP. But the oxidation of glucose to pyruvate
produces a total of 4 moles of ATP. Where do the remaining 2 moles of ATP come from?
a. One mole of glucose yields 2 moles of glyceraldehyde 3-phosphate.
b. Two moles of ATP are used during the conversion of glucose to glyceraldehyde 3phosphate.
c. Glycolysis produces 2 moles of NADH.
d. Fermentation of pyruvate to lactic acid yields 2 moles of ATP.
e. Fermentation of pyruvate to lactic acid yields 2 moles of NAD+.
Answer: a
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 173
Bloom’s Category: 4. Analyzing
20. The end product of glycolysis is
a. pyruvate.
b. the starting point for pyruvate oxidation.
c. the starting point for the fermentation pathway.
d. Both a and b
e. All of the above
Answer: e
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 2. Understanding
21. In the first reaction of glycolysis, glucose receives a phosphate group from ATP. This
reaction is
a. respiration.
b. a redox reaction.
c. exergonic.
d. endergonic.
e. fermentation.
Answer: d
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 2. Understanding
22. For glucose to be used as an energy source, it is necessary that
a. glucose be formed from fructose.
b. glucose phosphate be formed from fructose phosphate.
c. glucose be degraded to carbon dioxide.
d. two ATP molecules be invested in the system.
e. None of the above
Answer: d
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 2. Understanding
23. ATP is used to drive the first five reactions of glycolysis because
a. nonspontaneous reactions are exergonic.
b. the breakdown of ATP to ADP is exergonic.
c. the breakdown of ATP to ADP is endergonic.
d. when ATP is broken down to ADP, Pi is released.
e. ADP possesses more free energy than ATP does.
Answer: b
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 2. Understanding
24. The first five reactions of the glycolytic pathway result in
a. the addition of phosphates, modification of sugars, and formation of G3P.
b. oxidative steps, proton pumping, and reactions with oxygen.
c. the oxidation of pyruvate and formation of acetyl CoA.
d. the removal of hydrogen and protons from glucose.
e. None of the above
Answer: a
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 2. Understanding
25. The free energy released during the oxidation of glyceraldehyde 3-phosphate to 1,3bisphosphoglycerate is
a. used to oxidize NADH.
b. lost as heat.
c. used to synthesize ATP.
d. used to reduce NAD+.
e. stored in lactic acid.
Answer: d
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 2. Understanding
26. The end result of glycolysis is the
a. creation of 38 molecules of ATP.
b. reduction of 8 molecules of NAD.
c. formation of 2 molecules of pyruvate.
d. conversion of 1 molecule of glucose to lactic acid.
e. None of the above
Answer: c
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 1. Remembering
27. Within the cell, the pyruvate dehydrogenase complex, a multienzyme complex of the
citric acid cycle, is located in the
a. thylakoids.
b. cytoplasm.
c. chloroplast.
d. mitochondrial matrix.
e. plasma membrane.
Answer: d
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 1. Remembering
28. Substrate-level phosphorylation is the transfer of a(n)
a. phosphate to a protein.
b. phosphate to a substrate.
c. phosphate to an ADP.
d. ATP to a protein.
e. phosphate from ATP to a substrate.
Answer: c
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 1. Remembering
29. Some of the free energy released by oxidation of pyruvate to acetate is stored in
acetyl CoA. How does acetyl CoA store free energy?
a. Acetyl CoA has a higher free energy than acetate.
b. Acetyl CoA is an electron carrier.
c. Acetyl CoA is a phosphate donor.
d. Acetate + CoA → acetyl CoA is an exergonic reaction.
e. Reduction of acetyl CoA is coupled to ATP synthesis.
Answer: a
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 2. Understanding
30. During glycolysis, for each mole of glucose oxidized to pyruvate,
a. 6 moles of ATP are produced.
b. 2 moles of ATP are produced.
c. 4 moles of ATP are produced.
d. 2 moles of NAD+ are produced.
e. no ATP is produced.
Answer: c
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 3. Applying
31. Which process converts glucose to pyruvate, generating a small amount of ATP but
no carbon dioxide?
a. Pyruvate oxidation
b. Glycolysis
c. The citric acid cycle
d. Respiratory chain
e. Gluconeogenesis
Answer: b
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 1. Remembering
32. Pyruvate oxidation generates
a. acetate.
b. NADH + H+ from NAD+.
c. a change in free energy.
d. CO2.
e. All of the above
Answer: e
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 175
Bloom’s Category: 1. Remembering
33. During the citric acid cycle, energy stored in acetyl CoA is used to
a. create a proton gradient.
b. drive the reaction ADP + Pi → ATP.
c. reduce NAD+ to NADH.
d. drive the reaction oxaloacetate → citric acid.
e. reduce FAD to FADH2.
Answer: d
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 175
Bloom’s Category: 2. Understanding
34. The citric acid cycle begins with
a. glucose.
b. pyruvate.
c. acetyl CoA.
d. NADH + H+.
e. ATP synthase.
Answer: c
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 175
Bloom’s Category: 1. Remembering
35. During the citric acid cycle, oxidative steps are coupled to
a. oxidative phosphorylation.
b. the oxidation of water.
c. the oxidation of electron carriers.
d. the hydrolysis of ATP.
e. the reduction of electron carriers.
Answer: e
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 175
Bloom’s Category: 2. Understanding
36. More free energy is released during the citric acid cycle than during glycolysis, but
only 1 mole of ATP is produced for each mole of acetyl CoA that enters the cycle. Most
of the remaining free energy produced during the citric acid cycle is
a. used to synthesize GTP.
b. used to reduce electron carriers.
c. lost as heat.
d. used to reduce pyruvate.
e. converted to kinetic energy.
Answer: b
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 175
Bloom’s Category: 4. Analyzing
37. For the citric acid cycle to proceed, it is necessary for
a. pyruvate to bind to oxaloacetate.
b. carbon dioxide to bind to oxaloacetate.
c. an acetyl group to bind to oxaloacetate.
d. water to be oxidized.
e. None of the above
Answer: c
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 176
Bloom’s Category: 2. Understanding
38. Which of the following is produced during the citric acid cycle?
a. FAD
b. Pyruvate
c. Reduced electron carriers
d. Lactic acid
e. Water
Answer: c
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 177
Bloom’s Category: 2. Understanding
39. Animals breathe in air containing oxygen and breathe out air with less oxygen and
more carbon dioxide. The carbon dioxide comes from
a. hydrocarbons and the air.
b. the citric acid cycle.
c. glycolysis.
d. waste products.
e. All of the above
Answer: b
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 177
Bloom’s Category: 2. Understanding
40. How does the reduction of pyruvate to lactic acid during fermentation allow
glycolysis to continue in the absence of oxygen?
a. Water is formed during this reaction.
b. This reaction is a kinase reaction.
c. This reaction is coupled to the oxidation of NADH to NAD+.
d. This reaction is coupled to the formation of ATP.
e. This reaction is coupled to the reduction of NAD+ to NADH.
Answer: c
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 177
Bloom’s Category: 2. Understanding
41. Which of the following statements about the electron transport chain is true?
a. Electrons are received from NADH and FADH2.
b. Electrons are passed from donor to recipient carrier molecules in a series of oxidation–
reduction reactions.
c. Usually the terminal electron acceptor is oxygen.
d. Most of the enzymes are part of the inner mitochondrial membrane.
e. All of the above
Answer: e
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178
Bloom’s Category: 4. Analyzing
42. The electron transport chain contains four large protein complexes: NADH-Q
reductase complex, succinate dehydrogenase, cytochrome c reductase complex, and
cytochrome c oxidase complex. These proteins
a. are integral proteins.
b. change in a similar way when reduced.
c. regulate the passage of water through the respiratory chain.
d. oxidize NADH.
e. complete oxidation of pyruvate to acetate.
Answer: a
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178
Bloom’s Category: 1. Remembering
43. Animals inhale air containing oxygen and exhale air with less oxygen and more
carbon dioxide. After inhalation, the oxygen missing from the air will mostly be found in
a. the carbon dioxide that is exhaled.
b. water.
c. organic molecules.
d. ethanol.
e. lactate.
Answer: b
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178
Bloom’s Category: 2. Understanding
44. Electron transport within NADH-Q reductase, cytochrome reductase, and cytochrome
oxidase can be coupled to proton transport from the mitochondrial matrix to the space
between the inner and outer mitochondrial membranes, because those protein complexes
are
a. in the mitochondrial matrix.
b. within the inner mitochondrial membrane.
c. in the space between the inner and outer mitochondrial membranes.
d. in the cytoplasm.
e. loosely attached to the inner mitochondrial membrane.
Answer: b
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178
Bloom’s Category: 1. Remembering
45. Water is a by-product of cellular respiration. The water is produced as a result of the
a. combining of carbon dioxide with protons.
b. conversion of pyruvate to acetyl CoA.
c. degradation of glucose to pyruvate.
d. reduction of oxygen at the end of the electron transport chain.
e. None of the above
Answer: d
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178
Bloom’s Category: 2. Understanding
46. The oxidizing agent at the end of the electron transport chain is
a. O2.
b. NAD+.
c. ATP.
d. FAD.
e. ubiquinone.
Answer: a
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178
Bloom’s Category: 2. Understanding
47. Which of the following events occurs in the electron transport chain?
a. CO2 is released.
b. CO2 is reduced.
c. Cytochromes, FADH, and NADH are oxidized.
d. Only NAD+ is reduced.
e. None of the above
Answer: c
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178
Bloom’s Category: 1. Remembering
48. The electron transport chain contains four large protein complexes (I, II, III, and IV),
cytochrome c, and ubiquinone. The function of these molecules is to
a. transport electrons.
b. ensure the production of water and oxygen.
c. regulate the passage of water through the chain.
d. oxidize NADH.
e. None of the above
Answer: a
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178
Bloom’s Category: 2. Understanding
49. The drug 2,4-dinitrophenol (DNP) destroys the proton gradient across the inner
mitochondrial membrane. What would be the effect of incubating isolated mitochondria
in a solution of DNP?
a. Oxygen would no longer be reduced to water.
b. No ATP would be made during transport of electrons down the respiratory chain.
c. Mitochondria would show a burst of increased ATP synthesis.
d. Glycolysis would stop.
e. Mitochondria would switch from glycolysis to fermentation.
Answer: b
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 179
Bloom’s Category: 3. Applying
50. The hydrogen ion gradient is maintained by
a. electron transport and proton pumping.
b. the splitting of water.
c. the ionization of glucose.
d. ATP synthase.
e. acetyl CoA.
Answer: a
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 179
Bloom’s Category: 2. Understanding
51. When hydrogen ions are pumped from the mitochondrial matrix across the inner
membrane into the intermembranous space, the result is the
a. formation of ATP.
b. reduction of NAD+.
c. creation of a proton gradient.
d. restoration of the Na+–K+ balance across the membrane.
e. reduction of glucose to lactic acid.
Answer: c
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 179
Bloom’s Category: 2. Understanding
52. The chemiosmotic generation of ATP is driven by
a. osmotic movement of water into an area of high solute concentration.
b. the addition of protons to ADP and phosphate via enzymes.
c. oxidative phosphorylation.
d. the proton-motive force.
e. isocitrate dehydrogenase.
Answer: d
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 179
Bloom’s Category: 2. Understanding
53. The component of aerobic respiration that produces the most ATP per mole of
glucose is
a. the electron transport chain.
b. the citric acid cycle.
c. glycolysis.
d. lactic acid fermentation.
e. alcoholic fermentation.
Answer: a
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 179
Bloom’s Category: 2. Understanding
54. According to the chemiosmotic theory, the energy for the synthesis of ATP during the
flow of electrons down the respiratory chain is provided directly by the
a. hydrolysis of GTP.
b. reduction of NAD+.
c. diffusion of protons.
d. reduction of FAD.
e. hydrolysis of ATP.
Answer: c
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 180
Bloom’s Category: 2. Understanding
55. The proton-motive force is
a. ATP synthase.
b. the proton concentration gradient and electric charge difference.
c. a metabolic pathway.
d. a redox reaction.
e. None of the above
Answer: b
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 180
Bloom’s Category: 1. Remembering
56. In some mammals, such as newborn humans and hibernating animals, body
temperature is raised by means of
a. the uncoupling of respiration by the protein thermogenin.
b. an increase in the rate of glycolysis.
c. shivering.
d. leakage of hydrogen ions across the cell’s plasma membrane.
e. cytochrome reductase.
Answer: a
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 181
Bloom’s Category: 1. Remembering
57. Oxygen is used by
a. glycolysis.
b. the citric acid cycle.
c. the electron transport chain.
d. substrate-level phosphorylation.
e. ATP synthase.
Answer: c
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 181
Bloom’s Category: 1. Remembering
58. The formation of ethanol from pyruvate is an example of
a. an exergonic reaction.
b. an extra source of energy as the result of glycolysis.
c. a fermentation process that takes place in the absence of oxygen.
d. cellular respiration.
e. None of the above
Answer: c
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 181
Bloom’s Category: 2. Understanding
59. Most ATP produced in our bodies is made
a. by glycolysis.
b. in the citric acid cycle.
c. using ATP synthase.
d. from photosynthesis.
e. by burning fat.
Answer: c
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 181
Bloom’s Category: 2. Understanding
60. Regardless of the electron or hydrogen acceptor employed, fermentation always
produces
a. AMP.
b. DNA.
c. Pi.
d. NAD+.
e. None of the above
Answer: d
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 2. Understanding
61. In the absence of oxygen, cells capable of fermentation
a. accumulate glucose.
b. no longer produce ATP.
c. accumulate pyruvate.
d. oxidize FAD.
e. oxidize NADH to produce NAD+.
Answer: e
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 2. Understanding
62. For bacteria to continue growing rapidly when they are shifted from an environment
containing oxygen to an anaerobic environment, they must
a. increase the rate of the citric acid cycle.
b. produce more ATP per mole of glucose during glycolysis.
c. produce ATP during the oxidation of NADH.
d. increase the rate of transport of electrons down the respiratory chain.
e. increase the rate of the glycolytic reactions.
Answer: e
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 2. Understanding
63. In human muscle cells, the fermentation process produces
a. lactic acid.
b. 12 moles of ATP.
c. pyruvic acid.
d. an excessive amount of energy.
e. None of the above
Answer: a
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 1. Remembering
64. In alcoholic fermentation, NAD+ is produced during the
a. oxidation of pyruvate to acetyl CoA.
b. reduction of pyruvate to lactic acid.
c. reduction of acetaldehyde to ethanol.
d. hydrolysis of ATP to ADP.
e. oxidation of glucose.
Answer: c
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 2. Understanding
65. During the fermentation of one molecule of glucose, the net production of ATP is
_______ molecule(s).
a. one
b. two
c. three
d. six
e. eight
Answer: b
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 2. Understanding
66. Many species derive their energy from fermentation. The function of fermentation is
to
a. reduce NAD+.
b. oxidize CO2.
c. oxidize NADH + H+, ensuring a continued supply of ATP.
d. produce acetyl CoA.
e. None of the above
Answer: c
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 2. Understanding
67. Yeast cells tend to create anaerobic conditions because they use oxygen more quickly
than it can be replaced by diffusion through the cell membrane. For this reason, yeast
cells
a. exhibit a red pigment.
b. exhibit a green pigment.
c. die.
d. produce ethanol.
e. None of the above
Answer: d
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 2. Understanding
68. Before starch can be used for respiratory ATP production, it must be hydrolyzed to
a. pyruvate.
b. fatty acids.
c. amino acids.
d. glucose.
e. oxaloacetate.
Answer: d
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 184
Bloom’s Category: 1. Remembering
69. When acetyl CoA builds up in the cell, it increases the activity of the enzyme that
synthesizes oxaloacetate from pyruvate and carbon dioxide. Acetyl CoA is acting as a(n)
a. electron carrier.
b. substrate.
c. allosteric activator.
d. acetate donor.
e. proton pump.
Answer: c
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 185
Bloom’s Category: 1. Remembering
70. Fats are the preferred energy source in many organisms because
a. they are less dense than polysaccharides.
b. they have more C—H bonds and less C—OH bonds.
c. they are nonpolar.
d. fats do not bind to water.
e. they have essential roles as enzymes and structural elements.
Answer: b
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 185
Bloom’s Category: 4. Analyzing
71. A person on a severe diet will lose weight but is also likely to suffer from
undernutrition and eventually starvation. If a person does not eat enough to produce
sufficient ATP and NADH for biological activities, energy sources will be depleted in
what order?
a. Glycogen; fats; proteins
b. Fats; glycogen; proteins
c. Glycogen; proteins; fats
d. Fats; proteins; glycogen
e. Proteins; glycogen; fats
Answer: a
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 185
Bloom’s Category: 2. Understanding
72. When a cell needs energy, cellular respiration is regulated by isocitrate
dehydrogenase, an enzyme of the citric acid cycle. This enzyme is stimulated by
a. H+.
b. heat.
c. oxygen.
d. ADP.
e. None of the above
Answer: d
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 185
Bloom’s Category: 1. Remembering
73. The main control mechanism in glycolysis is the
a. enzyme isocitrate dehydrogenase.
b. negative feedback of citrate accumulation.
c. presence or absence of oxygen.
d. enzyme phosphofructokinase.
e. supply of NAD.
Answer: d
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 185
Bloom’s Category: 1. Remembering
74. In yeast, if the citric acid cycle is shut down because of a lack of oxygen, glycolysis
will probably
a. shut down.
b. increase.
c. produce more ATP per mole of glucose.
d. produce more NADH per mole of glucose.
e. produce acetyl CoA for fatty acid synthesis.
Answer: b
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 185
Bloom’s Category: 3. Applying
75. When the supply of acetyl CoA being produced exceeds the demands of the citric
acid cycle, some of the acetyl CoA is diverted to the synthesis of
a. pyruvate.
b. NAD.
c. proteins.
d. fatty acids.
e. lactic acid.
Answer: d
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 185
Bloom’s Category: 2. Understanding
76. If a cell has an abundant supply of ATP, acetyl CoA may be used
a. to enhance fermentation.
b. to enhance oxidative metabolism.
c. for fatty acid synthesis.
d. to convert glucose to glycogen.
e. None of the above
Answer: c
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 185
Bloom’s Category: 1. Remembering
77. When yeast cells are switched from aerobic to anaerobic growth conditions, the rate
of glycolysis increases. The rate of glycolysis is regulated by the concentration of
_______ in the cells.
a. ATP
b. acetyl CoA
c. oxaloacetate
d. FAD
e. protein
Answer: a
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 186
Bloom’s Category: 2. Understanding
Fill in the Blank
1. Muscle cells of marathon racers contain many mitochondria and use oxygen to break
down fats and carbohydrates. Ninety percent of marathon runners’ muscle is made up of
_______.
Answer: slow-twitch fibers
Textbook Reference: 9.0 Of mice and marathons
Page: 168
Bloom’s Category: 1. Remembering
2. _______ is a protein receptor that regulates the transcription of genes involved in the
breakdown of fat into ATP.
Answer: PPARδ
Textbook Reference: 9.0 Of mice and marathons
Page: 168
Bloom’s Category: 1. Remembering
3. In nonphotosynthetic organisms, the most common chemical fuel is _______.
Answer: glucose
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 169
Bloom’s Category: 1. Remembering
4. A chemical reaction resulting in the transfer of electrons or hydrogen atoms is called
a(n) _______ reaction.
Answer: redox
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 169
Bloom’s Category: 1. Remembering
5. Oxidation and _______ occur together.
Answer: reduction
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
Bloom’s Category: 2. Understanding
6. Fermentation occurs in the absence of oxygen and is therefore termed _______.
Answer: anaerobic
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
Bloom’s Category: 1. Remembering
7. The loss of an electron by a ferrous ion (Fe2+) to yield a ferric ion (Fe3+) is called
_______.
Answer: oxidation
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
Bloom’s Category: 2. Understanding
8. In a redox reaction, the reactant that becomes oxidized is called a(n) _______.
Answer: reducing agent
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
Bloom’s Category: 1. Remembering
9. Due to its ability to carry electrons and free energy, _______ is the most common
electron carrier in cells.
Answer: NAD
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 171
Bloom’s Category: 1. Remembering
10. The abbreviation for nicotinamide adenine dinucleotide is _______.
Answer: NAD
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 171
Bloom’s Category: 1. Remembering
11. The pathway for the oxidation of glucose to pyruvate is called _______.
Answer: glycolysis
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 172
Bloom’s Category: 1. Remembering
12. The enzyme-catalyzed transfer of phosphate groups to ADP molecules to form ATP
is called _______.
Answer: substrate-level phosphorylation
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 174
Bloom’s Category: 1. Remembering
13. Pyruvate is _______ to form acetate.
Answer: oxidized
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 175
Bloom’s Category: 1. Remembering
14. The oxidation of citrate to carbon dioxide is known as the _______.
Answer: citric acid cycle
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 175
Bloom’s Category: 1. Remembering
15. The chemiosmotic formation of ATP during the operation of the respiratory chain is
called _______.
Answer: oxidative phosphorylation
Textbook Reference: 9.3 How Does the Oxidation Phosphorylation Form ATP?
Page: 177
Bloom’s Category: 1. Remembering
16. The passing of electrons through a series of protein molecules is called the _______.
Answer: electron transport chain
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178
Bloom’s Category: 1. Remembering
17. The conversion of glucose to lactic acid is a form of _______.
Answer: fermentation
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 2. Understanding
18. During alcoholic fermentation, NAD+ is regenerated by the reduction of acetaldehyde
to _______.
Answer: ethanol
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 1. Remembering
19. Fatty acids must be converted to _______ before they can be used for respiratory
ATP production.
Answer: acetyl CoA
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 184
Bloom’s Category: 1. Remembering
20. The formation of glucose from glycolytic and citric acid intermediates is called
_______.
Answer: gluconeogenesis
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 186
Bloom’s Category: 1. Remembering
Diagram
1. Refer to the diagram below. The source of electrons for the electron transport chain is
a. FADH2.
b. NADH-Q reductase complex.
c. NADH + H+.
d. ubiquinone.
e. Both a and c
Answer: e
Textbook Reference: 9.3 How Does the Oxidation Phosphorylation Form ATP?
Page: 178
Bloom’s Category: 2. Understanding
STUDY GUIDE QUESTIONS
(By Jacalyn Newman)
Knowledge and Synthesis
1. Which of the following cellular metabolic processes is active in all cells, regardless of
the presence or the absence of oxygen?
a. The citric acid cycle
b. Electron transport
c. Glycolysis
d. Fermentation
e. Pyruvate oxidation
Answer: c
Feedback: Glycolysis proceeds during both fermentation and cellular respiration. Only in
cellular respiration is oxygen needed as the terminal electron acceptor of the pathway.
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
2. Which of the following statements regarding glycolysis is false?
a. A 6-C sugar is broken down to two 3-C molecules.
b. Two ATP molecules are consumed.
c. Glycolysis requires oxygen.
d. A net sum of two ATP molecules is generated.
e. Glycolysis occurs in the cytosol.
Answer: c
Feedback: During glycolysis, 6-C glucose is broken down into two 3-C pyruvate
molecules. In the process, four total ATP are produced, but two are consumed, leaving a
net production of two ATP molecules. No oxygen is required in glycolysis.
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 173
3. During which process is most ATP generated in the cell?
a. Glycolysis
b. The citric acid cycle
c. Electron transport coupled with chemiosmosis
d. Fermentation
e. Pyruvate oxidation
Answer: c
Feedback: Most of the ATP produced during cellular respiration is produced by electron
transport and chemiosmosis coupled in oxidative phosphorylation.
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 183
4. One purpose of the electron transport chain is to
a. cycle NADH + H+ back to NAD+.
b. use the intermediates from the citric acid cycle.
c. break down pyruvate.
d. increase the number of protons in the mitochondrial matrix.
e. consume excess ATP.
Answer: a
Feedback: The electron transport chain is responsible for oxidizing NADH + H+ back to
NAD+.
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178
5. Cellular respiration is allosterically controlled. Which of the following act(s) as
inhibitors at the various control points?
a. ATP
b. NADH
c. Both ATP and NADH
d. ADP
e. Both ADP and NADH
Answer: c
Feedback: Both ATP and NADH allosterically control metabolism. ATP controls both
phosphofructokinase and isocitrate dehydrogenase, which are commitment steps for
glycolysis and the citric acid cycle, respectively. NADH controls isocitrate
dehydrogenase.
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 186
6. Which of the following describes the role of the inner mitochondrial membrane?
a. It acts as an anchor for the membrane-associated enzymes of cellular respiration.
b. It allows for the establishment of a proton gradient.
c. It separates the mitocondria’s environment from that of the cytosol.
d. It anchors enzymes and allows for the establishment of the proton gradient, but it is not
involved in separating the contents of the mitochondria from the cytosol.
e. It anchors enzymes, allows for the establishment of the proton gradient, and is involved
in separating the contents of the mitochondria from the cytosol.
Answer: c
Feedback: The mitochondrial membrane is necessary for the anchoring of proteins as
well as the establishment of a barrier across which a gradient can be established.
Textbook Reference: 9.3 How Does the Oxidative Phosphorylation Form ATP?
Page: 179, Figure 9.9
7. In the following redox reaction, _______ is oxidized and _______ is reduced.
Glyceraldehyde 3-phosphate (G3P) + NAD+ + H+ + Pi → 1,3-Bisphosphoglycerate (BPG)
+ NADH
a. G3P; NAD+
b. BPG; NADH + H+
c. G3P; NADH + H+
d. NAD+; NADH + H+
e. The equation does not show a redox reaction.
Answer: a
Feedback: A molecule is oxidized when it loses electrons or protons and is reduced when
it gains electrons or protons. In this reaction, G3P donates electrons and therefore is
oxidized, while NAD+ accepts them and thus is reduced.
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 173
8. Which of the following statements about redox reactions is true?
a. Oxidizing agents accept electrons.
b. Oxidizing agents donate electrons.
c. A molecule that accepts electrons is said to be oxidized.
d. A molecule that donates electrons is said to be reduced.
e. Oxidizing agents accept electrons and are reduced in the process.
Answer: e
Feedback: Oxidizing agents accept electrons and cause oxidation of another molecule.
Reducing agents donate electrons and cause the reduction of another molecule.
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
9. Cyanide poisoning inhibits aerobic respiration at cytochrome c oxidase. Which of the
following is not a result of cyanide poisoning at the cellular level?
a. Reduction of oxygen to water
b. Cessation of ATP synthesis in the mitochondria because electron transport is never
completed
c. Switching of cells to anaerobic respiration and fermentation if possible
d. Continuation of glycolysis as long as NAD+ is available
e. Less acidic pH of the intermenbrane space
Answer: a
Feedback: Cyanide stops aerobic cellular respiration because cytochrome c oxidase loses
the ability to reduce oxygen to water. Those cells that can switch to anaerobic respiration
(fermentation) do so and use their remaining glucose more quickly. Cells that cannot
make that switch die.
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 179
10. Which of the following is correctly matched with its catabolic product?
a. polysaccharides → amino acids
b.
ol and fatty acids
c. proteins → glucose
d. polysaccharides → glycerol and fatty acids
e.
Answer: b
Feedback: Lipids are broken down into glycerol and fatty acids; polysaccharides are
broken down into glucose; proteins are broken down into amino acids. Nucleic acids are
converted into some amino acids and fed into the citric acid cycle.
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 184
11. The main function of cellular respiration is the
a. conversion of energy stored in the chemical bonds of glucose to an energy form that
the cell can use.
b. recovery of NAD+ from NADPH.
c. conversion of kinetic to potential energy.
d. creation of energy in the cell.
e. elimination of excess glucose from the cell.
Answer: a
Feedback: Cellular respiration is the cell’s way of converting potential energy in the
chemical bonds of glucose to potential energy that the cell ultimately can use.
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170
12. Which of the following statements concerning the synthesis of ATP in the
mitochondria is false?
a. ATP synthesis cannot occur without the presence of ATP synthase.
b. The proton-motive force is the establishment of a charge and concentration gradient
across the mitochondrial membrane.
c. The proton-motive force drives protons back across the membrane through channels
established by the ATP synthase channel protein.
d. The ATP synthase protein is composed of two units.
e. The intermembrane space is more basic than the mitochondrial matrix.
Answer: a
Feedback: Substrate level phosphorylation occurs in step 5 of the citric acid cycle in the
mitochondria. The intermembrane space is more acidic than the matrix.
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 179
13. Which of the following does not occur in the mitochondria of eukaryotic cells?
a. Fermentation
b. Oxidative phosphorylation
c. Citric acid cycle
d. Electron transport chain
e. Creation of a proton gradient
Answer: a
Feedback: Fermentation occurs in the cytosol, whereas all the other processes occur in
the mitochondria of eukaryotic cells.
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 172
14. The largest change in free energy during glycolysis occurs at which reaction?
a. Reaction 2: G6P → F6P
b. Reaction 5: DAP → G3P
c. Reaction 6: G3P → BPG + NADH
d. Reaction 7: BPG → 3PG + ATP
e. Reaction 8: 3PG → 2PG
Answer: c
Feedback: The largest change in free energy occurs in reaction 6, with more than 100
kcal/mol released.
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 173
15. Which of the following is recycled and reused in cellular metabolism?
a. ADP
b. NAD+
c. FAD
d. Pi
e. All of the above
Answer: e
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 172–173
16. For each molecule of glucose, how many ATPs are synthesized in fermentation?
a. 0
b. 1
c. 2
d. 3
e. 4
Answer: a
Feedback: ADP, NAD+, FAD, and Pi are all recycled and reused in the process of cellular
respiration.
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 172–173
17. If additional malate is added to a cell undergoing cellular respiration, there will be
a. an increase in CO2 production but no increase in ATP synthesis.
b. an increase in CO2 production and a decrease in ATP synthesis.
c. an increase in both the CO2 production and ATP synthesis.
d. a decrease in both the CO2 production and ATP synthesis.
e. no change in the rates of CO2 production or ATP synthesis.
Answer: c
Feedback: Additional malate will increase the carbon compounds cycling through the
citric acid cycle, resulting in an increase in the products of the citric acid cycle, including
ATP and CO2.
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 176–177
Application
1. Why is oxygen necessary for aerobic respiration?
Answer: Oxygen acts as the terminal electron acceptor in the electron transport pathway.
Without it, NADH + H+ cannot be cycled back to NAD+. The accumulated NADH + H+
acts as an inhibitor to the citric acid cycle and effectively shuts it down. Therefore, in the
absence of oxygen, a cell can only undergo glycolysis.
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 177
2. Glycolysis yields two molecules of pyruvate, two ATP, and two NADH + H+,
regardless of whether oxygen is present or not. What are the fates of these molecules in
the absence of oxygen? What would happen if NADH + H+ was not recycled?
Answer: In the absence of oxygen, pyruvate is either reduced to lactate (in lactic acid
fermentation) or it is metabolized and its metabolites are reduced to ethyl alcohol (in
alcoholic fermentation). In either case, NADH + H+ is the reducing agent, and it is
oxidized back to NAD+ in the process. The two molecules of ATP would be used as
cellular energy. If NADH + H+ was not oxidized to NAD+, there would eventually be no
NAD+ available for glycolysis.
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 181–182
3. Explain how the proton-motive force drives chemiosmosis.
Answer: The proton-motive force results in a concentration and charge gradient across
the mitochondrial membrane. For that gradient to equalize, the protons must flow through
a channel protein. If this channel protein has an associated ATP synthase, ATP is
generated as protons flow through.
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 179
4. The fate of acetyl CoA differs according to how much ATP is present in the cell.
Explain what happens to acetyl CoA when ATP is limited, and compare that to what
happens when acetyl CoA is abundant. How do these processes help regulate
metabolism?
Answer: If ATP is limited, acetyl CoA enters the citric acid cycle, and cellular respiration
utilizes it to produce ATP. If ATP is abundant, acetyl CoA is shuttled to fatty acid
synthesis, thus storing the energy in chemical bonds.
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 184
5. Cellular respiration occurs simultaneously with many other cellular processes.
Describe, in general, how cellular respiration interacts with other cellular metabolic
events.
Answer: Consult Figure 9.14 to see where different metabolic pathways in the cell
interact.
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 184
6. Compare and contrast energy yields from aerobic respiration and fermentation.
Answer: a
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
7. One of the by-products of aerobic cellular respiration is carbon dioxide. Assuming you
begin with labeled glucose, trace the fate of that molecule until carbon dioxide is
released.
Answer: Fermentation yields only two ATP. Cellular respiration yields 32 ATP.
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 173, 176
8. Identify the controlling steps of glycolysis, the citric acid cycle, and electron transport.
Which regulators affect each of these steps?
Answer: This control point for glycolysis is phosphofructo-kinase, which is inhibited by
ATP. This allows glycolysis to speed up during fermentation and slow down during
cellular respiration. The control point for the citric acid cycle is isocitrate dehydrogenase.
NADH + H+ and ATP inhibit the enzyme, and NAD+ and ADP are activators. Electron
transport is controlled by the amount of NADH + H+ fed in and by NADH-Q reductase.
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 186
9. Cyanide kills by inhibiting cytochrome oxidase in the mitochondria so that oxygen can
no longer be utilized and the electron transport chain halts. However, many cells in the
human body are capable of lactic acid fermentation. Since cyanide does not inhibit
glycolysis and fermentation, what could explain cyanide’s lethal affect on humans?
Answer: Based on what you have learned in this chapter, you should be thinking about
the reduced efficiency of glycolysis and fermentation for ATP synthesis, which is one
reason why oxygen deprivation is so deadly to humans. (And, as later chapters will show,
the resulting lactic acid buildup also causes problems.) In addition, not all cells are
capable of carrying out the reactions of fermentation. Brain cells, for example, will
simply die in the absence of oxygen.
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 181
10. Where do the bubbles in beer come from?
Answer: The bubbles in beer are bubbles of CO2 released during the fermentation of
pyruvate into ethyl alcohol. See Figure 9.12.
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
11. When a person consumes a packet of pure sugar and burns it for energy, where does
the carbon in the sugar ultimately go? Is the same true of the carbons in fat molecules
when a person loses weight?
Answer: The carbon in the sugar is exhaled in the form of CO2. When someone loses
weight, the carbon from the fat molecules is also exhaled in the form of CO2.
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 176
TEXTBOOK SELF-QUIZ
1. The role of oxygen gas in our cells is to
a. catalyze reactions in glycolysis.
b. produce CO2.
c. form ATP.
d. accept electrons from the respiratory chain.
e. react with glucose to split water.
Answer: d
2. Oxidation and reduction
a. entail the gain or loss of proteins.
b. are defined as the loss of electrons.
c. are both endergonic reactions.
d. always occur together.
e. proceed only under aerobic conditions.
Answer: d
3. NAD+ is
a. a type of organelle.
b. a protein.
c. present only in mitochondria.
d. a part of ATP.
e. formed in the reaction that produces ethanol.
Answer: e
4. Glycolysis
a. takes place in the mitochondrion.
b. produces no ATP.
c. has no connection with the respiratory chain.
d. is the same thing as fermentation.
e. reduces two molecules of NAD+ for every glucose molecule processed.
Answer: e
5. Fermentation
a. takes place in the mitochondrion.
b. takes place in all animal cells.
c. does not require O2.
d. requires lactic acid.
e. prevents glycolysis.
Answer: c
6. Which statement about pyruvate is not true?
a. It is the end product of glycolysis.
b. It becomes reduced during fermentation.
c. It is a precursor of acetyl CoA.
d. It is a protein.
e. It contains three carbon atoms.
Answer: d
7. The citric acid cycle
a. has no connection with the respiratory chain.
b. is the same thing as fermentation.
c. reduces two NAD+ for every glucose processed.
d. produces no ATP.
e. takes place in the mitochondrion.
Answer: e
8. The respiratory chain
a. is located in the mitochondrial matrix.
b. includes only peripheral membrane proteins.
c. always produces ATP.
d. reoxidizes reduced coenzymes.
e. operates simultaneously with fermentation.
Answer: d
9. Compared with fermentation, the aerobic pathways of glucose metabolism produce
a. more ATP.
b. pyruvate.
c. fewer protons for pumping in the mitochondria.
d. less CO2.
e. more oxidized coenzymes.
Answer: a
10. Which statement about oxidative phosphorylation is not true?
a. It forms ATP by the respiratory chain/ATP synthesis.
b. It is brought about by chemiosmosis.
c. It requires aerobic conditions.
d. It takes place in mitochondria.
e. Its functions can be served equally well by fermentation.
Answer: e
BIOPORTAL DIAGNOSTIC QUIZ (Personalized Study Plan Quiz)
(By Richard McCarty)
1. Which one of the following reactions is not an oxidation–reduction reaction?
a. NADH + ½O2 + H+ ↔ NAD+ + H2O
b. R—CH=CH—CH3 + H2O ↔ RCH2—CH(OH)—CH3
c. FAD + H2O ↔ FADH2 + ½O2
d. NADH + acetaldehyde ↔ NAD+ + ethanol
e. AH2 + B ↔ A +BH2
Answer: b
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170–171
Bloom’s Category: 2. Understanding
2. Glycolysis
a. is the conversion of glucose to two molecules of lactate.
b. is an endergonic reaction.
c. consumes ATP.
d. is an oxidation–reduction process.
e. releases carbon dioxide.
Answer: d
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170–171
Bloom’s Category: 2. Understanding
14. The conversion of malate to oxaloacetate in the citric acid cycle takes place with the
conversion of NAD+ to NADH. In this reaction, NAD+ is
a. the reducing agent.
b. the oxidizing agent.
c. reduced.
d. oxidized.
e. Both b and c
Textbook Reference: 9.1 How Does Glucose Oxidation Release Chemical Energy?
Page: 170–171
Bloom’s Category: 2. Understanding
4. The end products of glycolysis are
a. pyruvate.
b. pyruvate, ATP, and NAD+.
c. acetylCoA, ATP, and NAD+.
d. pyruvate, ATP, and NADH.
e. acetylCoA, ATP, and NADH.
Answer: d
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 173–174
Bloom’s Category: 2. Understanding
5. In the complete oxidation of glucose, 6 CO2 molecules are formed per glucose
oxidized. Choose from the list below the correct numbers of CO2 molecules released by
glycolysis (gly), the citric acid cycle (CAC), and pyruvate oxidation (pyr).
a. gly 1; CAC 3; pyr 2
b. gly 2; CAC 2; pyr 2
c. gly 1; CAC 4; pyr 1
d. gly 0; CAC 4; pyr 2
e. gly 0; CAC 6; pyr 0
Answer: d
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 173–177
Bloom’s Category: 4. Analyzing
6. Which of the statements below about the citric acid cycle is false?
a. The cycle releases less energy than glycolysis.
b. CO2 is released during operation of the cycle.
c. The cycle takes place in the mitochondrial matrix.
d. The cycle requires NAD+ and FAD.
e. The cycle does not operate under anaerobic conditions.
Answer: a
Textbook Reference: 9.2 What Are the Aerobic Pathways of Glucose Metabolism?
Page: 175–177
Bloom’s Category: 4. Analyzing
7. Which of the compounds listed below link(s) glycolysis and the citric acid cycle to the
mitochondrial electron transport chain?
a. NADH
b. ADP and Pi
c. FADH2
d. ATP
e. Both a and c
Answer: e
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 177–178
Bloom’s Category: 2. Understanding
8. The synthesis of ATP from ADP and Pi by mitochondria
a. is an oxidation–reduction reaction.
b. is linked to electron transport.
c. takes place in the absence of oxygen.
d. does not require energy.
e. accounts for a minor fraction of all of the ATP made by cells.
Answer: b
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 177–179
Bloom’s Category: 2. Understanding
9. The mitochondrial electron transport chain
a. is the site of most of the reactions of the citric acid cycle.
b. synthesizes ATP.
c. pumps protons into the mitochondrial matrix during electron transport.
d. oxidizes the intermediate electron carriers, NADH and FADH2.
e. oxidizes water to O2 and 2 H+.
Answer: d
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 177–179
Bloom’s Category: 2. Understanding
10. The mitochondrial ATP synthase
a. is an entirely integral membrane protein.
b. couples the synthesis of ATP to the flow of protons across the inner membrane from
inside to out.
c. is a soluble protein located in the mitochondrial matrix.
d. makes ATP at the expense of the proton gradient established by electron transport.
e. usually hydrolyzes ATP to establish a proton gradient.
Answer: d
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178–179
Bloom’s Category: 2. Understanding
11. The electron transport chain of mitochondria
a. is present in the outer membrane of the mitochondrion.
b. contains cytochromes and proteins containing flavins (FAD).
c. reduces NAD+.
d. generates an H+ gradient such that the outside of the mitochondrion is more basic than
the inside.
e. makes ATP.
Answer: b
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178–179
Bloom’s Category: 1. Remembering
12. The synthesis of ATP from ADP and Pi is an _______ reaction. In mitochondria, ATP
synthesis is driven by the flow of _______ down the concentration and electrical gradient
established by _______.
a. endergonic; Na+ ions; electron transport
b. exergonc; protons; glycolysis
c. endergonic; protons; electron transport
d. exergonic; Na+ ions; glycolysis
e. endergonic; protons; citric acid cycle
Answer: c
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 178–181
Bloom’s Category: 2. Understanding
13. Reagents, such as dinitrophenol, increase the permeability of the mitochondrial inner
membrane to protons. The addition of dinitrophenol to a suspension of animal cells
should
a. decrease the rate of oxidation of NADH.
b. inhibit mitochondrial ATP synthesis.
c. increase lactic acid production.
d. decrease the rate of pyruvate oxidation.
e. stimulate ATP synthesis by mitochondria.
Answer: b
Textbook Reference: 9.3 How Does Oxidative Phosphorylation Form ATP?
Page: 181
Bloom’s Category: 4. Analyzing
14. Fermentation
a. results in the formation of lactic acid or ethanol.
b. completely oxidizes glucose to CO2 and H2O.
c. is not coupled to ATP synthesis.
d. occurs under aerobic conditions in yeasts.
e. is endergonic.
Answer: a
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 181–182
Bloom’s Category: 2. Understanding
15. Cyanide inhibits the enzyme in the mitochondrial electron transport chain that
reduces O2 to water. Suppose that you add cyanide to a suspension of muscle cells from a
rat. Which statement given below is the most accurate with respect to the effects of
cyanide on glucose catabolism?
a. The citric acid cycle and glycolysis would be inhibited.
b. The citric acid cycle would be inhibited, but glycolysis would not. Ethanol
accumulates.
c. The citric acid cycle and glycolysis would be stimulated.
d. The citric acid cycle would be inhibited, but glycolysis would not. Lactic acid
accumulates.
e. The citric acid cycle would not be inhibited, but glycolysis would.
Answer: d
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 4. Analyzing
16. What is the metabolic fate of pyruvate in anaerobic muscle?
a. It is converted to acetylCoA.
b. It is decarboxylated.
c. It is oxidized.
d. It is reduced to lactate.
e. It is converted to ethanol.
Answer: d
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182
Bloom’s Category: 1. Remembering
17. A suspension of yeast supplied with glucose as its source of energy was transferred
from an aerobic environment to an anaerobic one. What do you think would happen to
the rate of glucose utilization and the rate of ethanol production after the transfer?
a. Glucose usage would decrease; ethanol production would increase.
b. Glucose usage would increase; ethanol production would decrease.
c. Both glucose usage and ethanol production would increase.
d. Both glucose usage and ethanol production would be unchanged.
e. Glucose usage would not change; ethanol production would increase.
Answer: c
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182–183
Bloom’s Category: 3. Applying
18. Most of the ATP made during the complete oxidation of glucose to CO2 and water is
a. made by the mitochondrial ATP synthase.
b. from substrate-level phosphorylation.
c. synthesized by the sodium–potassium ATPase.
d. synthesized in the cytosol.
e. made directly by the citric acid cycle.
Answer: a
Textbook Reference: 9.4 How Is Energy Harvested from Glucose in the Absence of
Oxygen?
Page: 182–183
Bloom’s Category: 2. Understanding
19. Triglycerides are major energy storage molecules. Which statement about the
complete oxidation of triglycerides to CO2 and water and the oxidation of glucose to two
molecules of pyruvate is correct?
a. They are both endergonic.
b. Both the complete oxidation of triglycerides and that of glucose to pyruvate use the
citric acid cycle.
c. Acetyl CoA is an intermediate in the breakdown of both glucose to pyruvate and
triglycerides.
d. Only glucose oxidation uses the glycolytic pathway.
e. Carbon dioxide is released by both pathways.
Answer: d
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 184
Bloom’s Category: 4. Analyzing
20. Acetyl CoA
a. is formed within mitochondria by the reduction of pyruvate.
b. is formed within mitochondria by the oxidation of fatty acids.
c. is formed in the cytoplasm by the oxidation of glucose.
d. is used for the synthesis of sugars.
e. is formed in the cytosol during the complete oxidation of glucose.
Answer: e
Textbook Reference: 9.5 How Are Metabolic Pathways Interrelated and Regulated?
Page: 184–185
Bloom’s Category: 2. Understanding