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a. a short-term energy-storagecompound.
b. the cell’s principalcompound for energy transfers.
c. synthesized withinmitochondria.
d. the molecule all living cellsrely on to do work.
2. Which of the followingstatements about metabolic pathways is false?
c. Almost all are anabolic.
3. Which of the followingstatements about metabolic pathways is true?
e. Each one is regulated byspecific enzymes.
4. When a molecule loseshydrogen atoms (as opposed to hydrogen ions), it becomes
5. In the conversion ofsuccinate to fumarate, hydrogen atoms are transferred to FAD. The conversion ofsuccinate and FAD to fumarate and FADH2 is an example of
e. a redox reaction.
6. The oxidation of malate tooxaloacetate is coupled to the reduction of NAD+ to NADH + H+.NAD+ is a(n)
b. oxidizing agent.
7. Which of the followingprocesses occurs when oxygen is unavailable?
8. In all cells, glucosemetabolism begins with
9. When NADH donates twoelectrons to ubiquinone during respiration, ubiquinone is
10. The end product of glycolysisis
b. the starting point forpyruvate oxidation.
c. the starting point for thefermentation pathway.
11. Which of the followingoxidizes other compounds by gaining free energy and hydrogen atoms and reducesother compounds by giving up free energy and hydrogen atoms?
12. The function of NAD+is to
c. carry hydrogen atoms andfree energy from compounds being oxidized and to give hydrogen atoms and freeenergy to compounds being reduced.
a. is a key electron carrierin redox reactions.
14. In the cell, the site ofoxygen utilization is the
15. In the first reaction ofglycolysis, glucose receives a phosphate group from ATP. This reaction is
16. During the energy-primingportion of glycolysis, the phosphates from ATP molecules are
a. added to the first andsixth carbons.
17. In order for glucose to beused as an energy source, it is necessary that
d. two ATP molecules beinvested in the system.
18. ATP is used to drive thefirst five reactions of glycolysis because
b. the breakdown of ATP to ADPis exergonic.
19. The first five reactionsof the glycolytic pathway result in
a. the addition of phosphates,modification of sugars, and formation of G3P.
20. The free energy releasedduring the oxidation of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerateis
d. used to reduce NAD+.
21. The end result ofglycolysis is the
c. formation of 2 molecules ofpyruvate.
22. Within the cell, thepyruvate dehydrogenase complex, a multi-enzyme complex of the citric acidcycle, is located in the
d. mitochondrial membrane.
23. Pyruvate oxidationgenerates
b. NADH + H+ from NAD+.
c. a change in free energy.
d. a capture of energy.
24. In steps 6 through 10 ofglycolysis, the conversion of one mole of glyceraldehyde 3-phosphate topyruvate yields 2 moles of ATP. But the oxidation of glucose to pyruvateproduces a total of 4 moles of ATP. Where do the remaining 2 moles of ATP comefrom?
a. One mole of glucose yields2 moles of glyceraldehyde 3-phosphate.
25. Substrate-levelphosphorylation is the transfer of a(n)
c. phosphate to an ADP.
26. Some of the free energyreleased by oxidation of pyruvate to acetate is stored in acetyl CoA. How doesacetyl CoA store free energy?
a. Acetyl CoA has a higherfree energy than acetate.
27. During the citric acidcycle, energy stored in acetyl CoA is used to
d. drive the reactionoxaloacetate ®citric acid.
28. Which of the following isproduced during the citric acid cycle?
c. Reduced electron carriers
29. The citric acid cyclebegins with
c. acetyl CoA.
30. During the citric acidcycle, oxidative steps are coupled to
e. the reduction of electroncarriers.
31. For the citric acid cycleto proceed, it is necessary for
c. an acetyl group to bind tooxaloacetate.
32. How does the reduction ofpyruvate to lactic acid during fermentation allow glycolysis to continue in theabsence of oxygen?
c. This reaction is coupled tothe oxidation of NADH to NAD+.
33. The formation of ethanolfrom pyruvate is an example of
c. a fermentation process thattakes place in the absence of oxygen.
34. Regardless of the electronor hydrogen acceptor employed, fermentation always produces
35. During glycolysis, foreach mole of glucose oxidized to pyruvate,
c. 4 moles of ATP areproduced.
36. Animals breathe in aircontaining oxygen and breathe out air with less oxygen and more carbon dioxide.The carbon dioxide comes from
b. the citric acid cycle.
37. For glycolysis tocontinue, all cells require
38. In the absence of oxygen,cells capable of fermentation
e. oxidize NADH to produce NAD+.
39. For bacteria to continuegrowing rapidly when they are shifted from an environment containing oxygen toan anaerobic environment, they must
e. increase the rate of theglycolytic reactions.
40. More free energy isreleased during the citric acid cycle than during glycolysis, but only 1 moleof ATP is produced for each mole of acetyl CoA that enters the cycle. Most ofthe remaining free energy that is produced during the citric acid cycle is
b. used to reduce electroncarriers.
41. In human muscle cells, thefermentation process produces
a. lactic acid.
42. The oxidation of pyruvateto carbon dioxide is called
b. the citric acid cycle.
43. In alcoholic fermentation,NAD+ is produced during the
c. reduction of acetaldehydeto ethanol.
44. During the fermentation ofone molecule of glucose, the net production of ATP is _______ molecule(s).
45. Many species derive theirenergy from fermentation. The function of fermentation is to
c. oxidize NADH + H+,ensuring a continued supply of ATP.
46. Yeast cells tend to createanaerobic conditions because they use oxygen more quickly than it can bereplaced by diffusion through the cell membrane. For this reason, yeast cells
d. produce ethanol.
47. The oxidizing agent at theend of the electron transport chain is
48. Which of the followingevents occurs in the electron transport chain?
c. Cytochromes, FADH, and NADHare oxidized.
49. The electron transportchain contains four large protein complexes (I, II, III, and IV), cytochrome c,and ubiquinone. The function of these molecules is to
a. transport electrons.
50. Oxygen is used by
51. Which of the followingstatements about the electron transport chain is true?
a. Electrons are received fromNADH and FADH2.
b. Electrons are passed fromdonor to recipient carrier molecules in a series of oxidation-reductionreactions.
c. Usually the terminalelectron acceptor is oxygen.
d. Most of the enzymes arepart of the inner mitochondrial membrane.
52. The electron transportchain contains four large protein complexes: NADH-Q reductase complex,succinate dehydrogenase, cytochrome c reductase complex, and cytochrome c oxidasecomplex. These proteins
a. are integral proteins.
53. Animals inhale aircontaining oxygen and exhale air with less oxygen and more carbon dioxide.After inhalation, the extra oxygen from the air will mostly be found in
54. 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 ofDNP?
b. No ATP would be made duringtransport of electrons down the respiratory chain.
55. Electron transport withinNADH-Q reductase, cytochrome reductase, and cytochrome oxidase can be coupledto proton transport from the mitochondrial matrix to the space between theinner and outer mitochondrial membranes, because those protein complexes are
b. within the innermitochondrial membrane.
56. Water is a by-product ofcellular respiration. The water is produced as a result of the
d. reduction of oxygen at theend of the electron transport chain.
57. According to thechemiosmotic theory, the energy for the synthesis of ATP during the flow ofelectrons down the respiratory chain is provided directly by the
c. diffusion of protons.
58. The proton-motive force is
b. the proton concentrationgradient and electric charge difference.
59. The chemiosmoticgeneration of ATP is driven by
d. a difference in H+concentration on both sides of a membrane.
60. The hydrogen ion gradientis maintained by
a. electron transport andproton pumping.
61. When hydrogen ions arepumped from the mitochondrial matrix across the inner membrane into theintermembraneous space, the result is the
c. creation of a protongradient.
62. The chemiosmoticgeneration of ATP is driven by
d. the proton-motive force.
63. The component of aerobicrespiration that produces the most ATP per mole of glucose is
a. the electron transportchain.
64. In some mammals, such asnew born humans and hibernating animals, body temperature is raised by means of
a. the uncoupling ofrespiration by the protein thermogenin.
65. Most ATP produced in ourbodies is made
c. using ATP synthase.
66. Which process convertsglucose to pyruvate, generating a small amount of ATP but no carbon dioxide?
67. Before starch can be usedfor respiratory ATP production, it must be hydrolyzed to
68. When yeast cells areswitched from aerobic to anaerobic growth conditions, the rate of glycolysisincreases. The rate of glycolysis is regulated by the concentration of _______in the cells.
69. When acetyl CoA builds upin the cell, it increases the activity of the enzyme that synthesizesoxaloacetate from pyruvate and carbon dioxide. Acetyl CoA is acting as a(n)
c. allosteric activator.
70. When a cell needs energy,cellular respiration is regulated by isocitrate dehydrogenase, an enzyme of thecitric acid cycle. This enzyme is stimulated by
71. The main control mechanismin glycolysis is the
d. the enzymephosphofructokinase.
72. In yeast, if the citricacid cycle is shut down because of a lack of oxygen, glycolysis will probably
73. When the supply of acetylCoA being produced exceeds the demands of the citric acid cycle, some of theacetyl CoA is diverted to the synthesis of
d. fatty acids.
74. If a cell has an abundantsupply of ATP, acetyl CoA may be used
c. for fatty acid synthesis.
1. Muscle cells of marathonracers contain many mitochondria and use oxygen to break down fats andcarbohydrates. Ninety percent of marathon runners’ muscle is made up of_______.
2. In nonphotosyntheticorganisms, the most common chemical fuel is _______.
3. Oxidation and _______ occurtogether.
4. A chemical reaction resultingin the transfer of electrons or hydrogen atoms is called a _______ reaction.
5. Fermentation occurs in theabsence of oxygen and is therefore termed _______.
6. The loss of an electron bya ferrous ion (Fe2+) to yield a ferric ion (Fe3+) iscalled _______.
7. Due to its ability to carryelectrons and free energy, _______ is the most common electron carrier incells.
8. The abbreviation fornicotinamide adenine dinucleotide is _______.
9. In a redox reaction, thereactant that becomes oxidized is called a _______.
10. The pathway for theoxidation of glucose to pyruvate is called _______.
11. Pyruvate is _______ toform acetate.
12. The enzyme-catalyzedtransfer of phosphate groups to ADP molecules to form ATP is called _______.
13. The oxidation of citrateto carbon dioxide is known as the _______.
14. The conversion of glucoseto lactic acid is a form of _______.
15. During alcoholicfermentation, NAD+ is regenerated by the reduction of acetaldehydeto _______.
16. The chemiosmotic formationof ATP during the operation of the respiratory chain is called _______.
17. The passing of electronsthrough a series of protein molecules is called the _________.
18. Fatty acids must beconverted to _______ before they can be used for respiratory ATP production.
19. An enzyme that transfers aphosphate group from ATP to another protein is called a(n) _______.
20. The formation of glucosefrom glycolytic and citric acid immediates is called _______.
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