Practice Questions for Chapters 9-10



Practice Questions for Chapters 9-10

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

____ 1. What is the term for metabolic pathways that release stored energy by breaking down complex molecules?

|a. |anabolic pathways |

|b. |catabolic pathways |

|c. |fermentation pathways |

|d. |thermodynamic pathways |

|e. |bioenergetic pathways |

____ 2. What is the term used for the metabolic pathway in which glucose (C6H12O6) is degraded to carbon dioxide (CO2) and water?

|a. |cellular respiration |

|b. |glycolysis |

|c. |fermentation |

|d. |citric acid cycle |

|e. |oxidative phosphorylation |

____ 3. Which of the following statements concerning the metabolic degradation of glucose (C6H12O6) to carbon dioxide (CO2) and water is (are) true?

|a. |The breakdown of glucose to carbon dioxide and water is exergonic. |

|b. |The breakdown of glucose to carbon dioxide and water has a free energy change of -686 kcal/mol. |

|c. |The breakdown of glucose to carbon dioxide and water involves oxidation-reduction or redox reactions. |

|d. |Only A and B are correct. |

|e. |A, B, and C are correct. |

____ 4. Which of the following statements is (are) correct about an oxidation-reduction (or redox) reaction?

|a. |The molecule that is reduced gains electrons. |

|b. |The molecule that is oxidized loses electrons. |

|c. |The molecule that is reduced loses electrons. |

|d. |The molecule that is oxidized gains electrons. |

|e. |Both A and B are correct. |

____ 5. Which statement is not correct with regard to redox (oxidation-reduction) reactions?

|a. |A molecule is reduced if it loses electrons. |

|b. |A molecule is oxidized if it loses electrons. |

|c. |An electron donor is called a reducing agent. |

|d. |An electron acceptor is called an oxidizing agent. |

|e. |Oxidation and reduction always go together. |

____ 6. The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction

|a. |gains electrons and gains energy. |

|b. |loses electrons and loses energy. |

|c. |gains electrons and loses energy. |

|d. |loses electrons and gains energy. |

|e. |neither gains nor loses electrons, but gains or loses energy. |

____ 7. When electrons move closer to a more electronegative atom, what happens?

|a. |Energy is released. |

|b. |Energy is consumed. |

|c. |The more electronegative atom is reduced. |

|d. |The more electronegative atom is oxidized. |

|e. |A and C are correct. |

____ 8. Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy?

|a. |The covalent bonds in organic molecules are higher energy bonds than those in water and carbon dioxide. |

|b. |Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher |

| |affinity for electrons (such as O).. |

|c. |The oxidation of organic compounds can be used to make ATP. |

|d. |The electrons have a higher potential energy when associated with water and CO2 than they do in organic compounds. |

|e. |The covalent bond in O2 is unstable and easily broken by electrons from organic molecules. |

____ 9. Which of the following statements describes the results of this reaction?

C6H12O6 + 6 O2 [pic] 6 CO2 + 6 H2O + Energy

|a. |C6H12O6 is oxidized and O2 is reduced. |

|b. |O2 is oxidized and H2O is reduced. |

|c. |CO2 is reduced and O2 is oxidized. |

|d. |C6H12O6is reduced and CO2 is oxidized. |

|e. |O2 is reduced and CO2 is oxidized. |

____ 10. When a glucose molecule loses a hydrogen atom (not a hydrogen ion) as the result of an oxidation-reduction reaction, the molecule becomes

|a. |dehydrogenated. |

|b. |hydrogenated. |

|c. |oxidized. |

|d. |reduced. |

|e. |an oxidizing agent. |

____ 11. When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a hydrogen ion) the molecule becomes

|a. |hydrogenated. |

|b. |oxidized. |

|c. |reduced. |

|d. |redoxed. |

|e. |a reducing agent. |

____ 12. Which of the following statements about NAD+ is false?

|a. |NAD+ is reduced to NADH during both glycolysis and the citric acid cycle. |

|b. |NAD+ has more chemical energy than NADH. |

|c. |NAD+ is reduced by the action of dehydrogenases. |

|d. |NAD+ can receive electrons for use in oxidative phosphorylation. |

|e. |In the absence of NAD+, glycolysis cannot function. |

____ 13. In order for NAD+ to remove electrons from glucose or other organic molecules, which of the following must be true?

|a. |The organic molecule or glucose must be negatively charged in order to reduce the positively charged NAD+. |

|b. |Oxygen must be present to oxidize the NADH produced back to NAD+. |

|c. |The free energy liberated when electrons are removed from the organic molecules must be greater than the energy required|

| |to give the electrons to NAD+. |

|d. |A and B are both correct. |

|e. |A, B, and C are all correct. |

____ 14. Where does glycolysis takes place?

|a. |mitochondrial matrix |

|b. |mitochondrial outer membrane |

|c. |mitochondrial inner membrane |

|d. |mitochondrial intermembrane space |

|e. |cytosol |

____ 15. The ATP made during glycolysis is generated by

|a. |substrate-level phosphorylation. |

|b. |electron transport. |

|c. |photophosphorylation. |

|d. |chemiosmosis. |

|e. |oxidation of NADH to NAD+. |

____ 16. The oxygen consumed during cellular respiration is involved directly in which process or event?

|a. |glycolysis |

|b. |accepting electrons at the end of the electron transport chain |

|c. |the citric acid cycle |

|d. |the oxidation of pyruvate to acetyl CoA |

|e. |the phosphorylation of ADP to form ATP |

____ 17. Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?

|a. |electron transport |

|b. |glycolysis |

|c. |the citric acid cycle |

|d. |oxidative phosphorylation |

|e. |chemiosmosis |

____ 18. Which of the following statements about glycolysis false?

|a. |Glycolysis has steps involving oxidation-reduction reactions. |

|b. |The enzymes of glycolysis are located in the cytosol of the cell. |

|c. |Glycolysis can operate in the complete absence of O2. |

|d. |The end products of glycolysis are CO2 and H2O. |

|e. |Glycolysis makes ATP exclusively through substrate-level phosphorylation. |

The figure below illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the following questions.

[pic]

____ 19. Which step shows a split of one molecule into two smaller molecules?

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 20. In which step is an inorganic phosphate added to the reactant?

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 21. In which reaction does an intermediate pathway become oxidized?

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 22. Which step involves an endergonic reaction?

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 23. Which step consists of a phosphorylation reaction in which ATP is the phosphate source?

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 24. Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed during glycolysis?

|a. |0% |

|b. |2% |

|c. |10% |

|d. |38% |

|e. |100% |

____ 25. During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is

|a. |transferred to ADP, forming ATP. |

|b. |transferred directly to ATP. |

|c. |retained in the pyruvate. |

|d. |stored in the NADH produced. |

|e. |used to phosphorylate fructose to form fructose-6-phosphate. |

____ 26. In addition to ATP, what are the end products of glycolysis?

|a. |CO2 and H2O |

|b. |CO2 and pyruvate |

|c. |NADH and pyruvate |

|d. |CO2 and NADH |

|e. |H2O, FADH2, and citrate |

____ 27. The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mole and the free energy for the reduction of NAD+ to NADH is +53 kcal/mole. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed?

|a. |Most of the free energy available from the oxidation of glucose is used in the production of ATP in glycolysis. |

|b. |Glycolysis is a very inefficient reaction, with much of the energy of glucose released as heat. |

|c. |Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis. |

|d. |There is no CO2 or water produced as products of glycolysis. |

|e. |Glycolysis consists of many enzymatic reactions, each of which extracts some energy from the glucose molecule. |

____ 28. Starting with one molecule of glucose, the "net" products of glycolysis are

|a. |2 NAD+, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O. |

|b. |2 NADH, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O. |

|c. |2 FADH2, 2 pyruvate, 4 ATP, and 2 H2O. |

|d. |6 CO2, 6 H2O, 2 ATP, and 2 pyruvate. |

|e. |6 CO2, 6 H2O, 36 ATP, and 2 citrate. |

____ 29. In glycolysis, for each molecule of glucose oxidized to pyruvate

|a. |2 molecules of ATP are used and 2 molecules of ATP are produced. |

|b. |2 molecules of ATP are used and 4 molecules of ATP are produced. |

|c. |4 molecules of ATP are used and 2 molecules of ATP are produced. |

|d. |2 molecules of ATP are used and 6 molecules of ATP are produced. |

|e. |6 molecules of ATP are used and 6 molecules of ATP are produced. |

____ 30. A molecule that is phosphorylated

|a. |has an increased chemical reactivity; it is primed to do cellular work. |

|b. |has a decreased chemical reactivity; it is less likely to provide energy for cellular work. |

|c. |has been oxidized as a result of a redox reaction involving the gain of an inorganic phosphate. |

|d. |has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate. |

|e. |has less energy than before its phosphorylation and therefore less energy for cellular work. |

____ 31. Which kind of metabolic poison would most directly interfere with glycolysis?

|a. |An agent that reacts with oxygen and depletes its concentration in the cell |

|b. |An agent that binds to pyruvate and inactivates it |

|c. |An agent that closely mimics the structure of glucose but is not metabolized |

|d. |An agent that reacts with NADH and oxidizes it to NAD+ |

|e. |An agent that blocks the passage of electrons along the electron transport chain |

____ 32. 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. These three steps result in the formation of

|a. |acetyl CoA, O2, and ATP. |

|b. |acetyl CoA, FADH2, and CO2. |

|c. |acetyl CoA, FAD, H2, and CO2. |

|d. |acetyl CoA, NADH, H+, and CO2. |

|e. |acetyl CoA, NAD+, ATP, and CO2. |

____ 33. Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO2) from one molecule of pyruvate?

|a. |lactate |

|b. |glyceraldehydes-3-phosphate |

|c. |oxaloacetate |

|d. |acetyl CoA |

|e. |citrate |

____ 34. During cellular respiration, acetyl CoA accumulates in which location?

|a. |cytosol |

|b. |mitochondrial outer membrane |

|c. |mitochondrial inner membrane |

|d. |mitochondrial intermembrane space |

|e. |mitochondrial matrix |

____ 35. How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?

|a. |2 |

|b. |4 |

|c. |6 |

|d. |8 |

|e. |10 |

____ 36. All of the following are functions of the citric acid cycle except

|a. |production of ATP. |

|b. |production of NADH. |

|c. |production of FADH2. |

|d. |release of carbon dioxide. |

|e. |adding electrons and protons to oxygen, forming water. |

Refer to the figure below, showing the citric acid cycle, as a guide to answer the following questions.

[pic]

____ 37. Starting with one molecule of isocitrate and ending with fumarate, what is the maximum number of ATP molecules that could be made through substrate-level phosphorylation?

|a. |1 |

|b. |2 |

|c. |11 |

|d. |12 |

|e. |24 |

____ 38. Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the citric acid cycle. Which intermediate would supply the carbon skeleton for synthesis of a five-carbon amino acid?

|a. |succinate |

|b. |malate |

|c. |citrate |

|d. |[pic]-ketoglutarate |

|e. |isocitrate |

____ 39. Starting with one molecule of citrate and ending with oxaloacetate, how many ATP molecules can be formed from oxidative phosphorylation (chemiosmosis)?

|a. |1 |

|b. |3 |

|c. |4 |

|d. |11 |

|e. |12 |

____ 40. How many ATP molecules could be made through substrate-level phosphorylation plus oxidative phosphorylation (chemiosmosis) if you started with three molecules of succinyl CoA and ended with oxaloacetate?

|a. |6 |

|b. |12 |

|c. |18 |

|d. |24 |

|e. |36 |

____ 41. How many molecules of carbon dioxide (CO2) would be produced by five turns of the citric acid cycle?

|a. |2 |

|b. |5 |

|c. |10 |

|d. |12 |

|e. |60 |

____ 42. How many reduced dinucleotides would be produced with four turns of the citric acid cycle?

|a. |1 FADH2 and 4 NADH |

|b. |2 FADH2 and 8 NADH |

|c. |4 FADH2 and 12 NADH |

|d. |1 FAD and 4 NAD+ |

|e. |4 FAD+ and 12 NAD+ |

____ 43. Starting with citrate, how many of the following would be produced with three turns of the citric acid cycle?

|a. |1 ATP, 2 CO2, 3 NADH, and 1 FADH2 |

|b. |2 ATP, 2 CO2, 1 NADH, and 3 FADH2 |

|c. |3 ATP, 3 CO2, 3 NADH, and 3 FADH2 |

|d. |3 ATP, 6 CO2, 9 NADH, and 3 FADH2 |

|e. |38 ATP, 6 CO2, 3 NADH, and 12 FADH2 |

____ 44. Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?

|a. |glycolysis and the oxidation of pyruvate to acetyl CoA |

|b. |oxidation of pyruvate to acetyl CoA and the citric acid cycle |

|c. |the citric acid cycle and oxidative phosphorylation |

|d. |oxidative phosphorylation and fermentation |

|e. |fermentation and glycolysis |

____ 45. For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle, what is the total number of NADH + FADH2 molecules produced?

|a. |4 |

|b. |5 |

|c. |6 |

|d. |10 |

|e. |12 |

____ 46. A young relative of yours has never had much energy. He goes to a doctor for help and is sent to the hospital for some tests. There they discover his 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 his condition?

|a. |His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane. |

|b. |His cells cannot move NADH from glycolysis into the mitochondria. |

|c. |His cells contain something that inhibits oxygen use in his mitochondria. |

|d. |His cells lack the enzyme in glycolysis that forms pyruvate. |

|e. |His cells have a defective electron transport chain, so glucose goes to lactate instead of to acetyl CoA. |

____ 47. Cellular respiration harvests the most chemical energy from which of the following?

|a. |substrate-level phosphorylation |

|b. |chemiosmotic phosphorylation |

|c. |converting oxygen to ATP |

|d. |transferring electrons from organic molecules to pyruvate |

|e. |generating carbon dioxide and oxygen in the electron transport chain |

____ 48. During aerobic respiration, electrons travel downhill in which sequence?

|a. |food [pic] citric acid cycle [pic] ATP [pic] NAD+ |

|b. |food [pic] NADH [pic] electron transport chain [pic] oxygen |

|c. |glucose [pic] pyruvate [pic] ATP [pic] oxygen |

|d. |glucose [pic] ATP [pic] electron transport chain [pic] NADH |

|e. |food [pic] glycolysis [pic] citric acid cycle [pic] NADH [pic] ATP |

____ 49. Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle?

|a. |pyruvate |

|b. |malate or fumarate |

|c. |acetyl CoA |

|d. |[pic]-ketoglutarate |

|e. |succinyl CoA |

____ 50. Where are the proteins of the electron transport chain located?

|a. |cytosol |

|b. |mitochondrial outer membrane |

|c. |mitochondrial inner membrane |

|d. |mitochondrial intermembrane space |

|e. |mitochondrial matrix |

____ 51. Which of the following describes the sequence of electron carriers in the electron transport chain, starting with the least electronegative?

|a. |ubiquinone (Q), cytochromes (Cyt), FMN, Fe•S |

|b. |cytochromes (Cyt), FMN, ubiquinone, Fe·S |

|c. |Fe•S, FMN, cytochromes (Cyt), ubiquinone |

|d. |FMN, Fe•S, ubiquinone, cytochromes (Cyt) |

|e. |cytochromes (Cyt), Fe•S, ubiquinone, FMN |

____ 52. During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?

|a. |NAD+ |

|b. |NADH |

|c. |ATP |

|d. |ADP + Pi |

|e. |FADH2 |

____ 53. The primary role of oxygen in cellular respiration is to

|a. |yield energy in the form of ATP as it is passed down the respiratory chain. |

|b. |act as an acceptor for electrons and hydrogen, forming water. |

|c. |combine with carbon, forming CO2. |

|d. |combine with lactate, forming pyruvate. |

|e. |catalyze the reactions of glycolysis. |

____ 54. Inside an active mitochondrion, most electrons follow which pathway?

|a. |glycolysis [pic] NADH [pic] oxidative phosphorylation [pic] ATP [pic] oxygen |

|b. |citric acid cycle [pic] FADH2 [pic] electron transport chain [pic] ATP |

|c. |electron transport chain [pic] citric acid cycle [pic]ATP [pic] oxygen |

|d. |pyruvate [pic] citric acid cycle [pic] ATP [pic] NADH [pic] oxygen |

|e. |citric acid cycle [pic] NADH [pic] electron transport chain [pic] oxygen |

____ 55. During oxidative phosphorylation, H2O is formed. Where does the oxygen for the synthesis of the water come from?

|a. |carbon dioxide (CO2) |

|b. |glucose (C6H12O6) |

|c. |molecular oxygen (O2) |

|d. |pyruvate (C3H3O3–) |

|e. |lactate (C3H5O3–-) |

____ 56. Which metabolic process is most closely associated with intracellular membranes?

|a. |substrate-level phosphorylation |

|b. |oxidative phosphorylation |

|c. |glycolysis |

|d. |the citric acid cycle |

|e. |alcohol fermentation |

____ 57. In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP?

|a. |energy released as electrons flow through the electron transport system |

|b. |energy released from substrate-level phosphorylation |

|c. |energy released from ATP synthase pumping hydrogen ions against their concentration gradient |

|d. |energy released from movement of protons through ATP synthase |

|e. |No external source of energy is required because the reaction is exergonic. |

____ 58. Energy released by the electron transport chain is used to pump H+ ions into which location?

|a. |cytosol |

|b. |mitochondrial outer membrane |

|c. |mitochondrial inner membrane |

|d. |mitochondrial intermembrane space |

|e. |mitochondrial matrix |

____ 59. During aerobic cellular respiration, a proton gradient in mitochondria is generated by ____ and used primarily for ____.

|a. |the electron transport chain; ATP synthesis |

|b. |the electron transport chain; substrate-level phosphorylation |

|c. |glycolysis; production of H2O |

|d. |fermentation; NAD+ reduction |

|e. |diffusion of protons; ATP synthesis |

____ 60. The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is

|a. |oxidation of glucose to CO2 and water. |

|b. |the thermodynamically favorable flow of electrons from NADH to the mitochondrial electron transport carriers. |

|c. |the final transfer of electrons to oxygen. |

|d. |the difference in H+ concentrations on opposite sides of the inner mitochondrial membrane. |

|e. |the thermodynamically favorable transfer of phosphate from glycolysis and the citric acid cycle intermediate molecules |

| |of ADP. |

____ 61. A major function of the mitochondrial inner membrane is the conversion of energy from electrons to the stored energy of the phosphate bond in ATP. To accomplish this function, the inner mitochondrial membrane must have all of the following features except

|a. |carrier proteins to accept electrons from NADH. |

|b. |integral, transverse ATP synthase. |

|c. |proton pumps embedded in the membrane. |

|d. |the electron transport chain of proteins. |

|e. |high permeability to protons. |

____ 62. When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the

|a. |formation of ATP. |

|b. |reduction of NAD+. |

|c. |restoration of the Na+/K+ balance across the membrane. |

|d. |creation of a proton gradient. |

|e. |lowering of pH in the mitochondrial matrix. |

____ 63. Where is ATP synthase located in the mitochondrion?

|a. |cytosol |

|b. |electron transport chain |

|c. |outer membrane |

|d. |inner membrane |

|e. |mitochondrial matrix |

____ 64. It is possible to prepare vesicles from portions of the inner membrane of the mitochondrial components. Which one of the following processes could still be carried on by this isolated inner membrane?

|a. |the citric acid cycle |

|b. |oxidative phosphorylation |

|c. |glycolysis and fermentation |

|d. |reduction of NAD+ |

|e. |both the citric acid cycle and oxidative phosphorylation |

____ 65. The primary function of the mitochondrion is the production of ATP. To carry out this function, the mitochondrion must have all of the following except

|a. |the membrane-bound electron transport chain carrier molecules. |

|b. |proton pumps embedded in the inner mitochondrial membrane. |

|c. |enzymes for glycolysis. |

|d. |enzymes for the citric acid cycle. |

|e. |mitochondrial ATP synthase. |

____ 66. Which process could be compared to how rushing steam turns a water wheel?

|a. |the citric acid cycle |

|b. |ATP synthase activity |

|c. |formation of NADH in glycolysis |

|d. |oxidative phosphorylation |

|e. |the electron transport system |

____ 67. How many molecules of carbon dioxide (CO2) would be released from the complete aerobic respiration of a molecule of sucrose (C12H22 O11), a disaccharide?

|a. |2 |

|b. |3 |

|c. |6 |

|d. |12 |

|e. |38 |

____ 68. Each time a molecule of glucose (C6H12O6) is completely oxidized via aerobic respiration, how many oxygen molecules (O2). are required?

|a. |1 |

|b. |2 |

|c. |6 |

|d. |12 |

|e. |38 |

____ 69. Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water?

|a. |glycolysis |

|b. |fermentation |

|c. |oxidation of pyruvate to acetyl CoA |

|d. |citric acid cycle |

|e. |oxidative phosphorylation (chemiosmosis) |

____ 70. Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose (C6H12O6) in cellular respiration?

|a. |2 |

|b. |4 |

|c. |15 |

|d. |38 |

|e. |76 |

____ 71. Assume a mitochondrion contains 58 NADH and 19 FADH2. If each of the 77 dinucleotides were used, approximately how many ATP molecules could be generated as a result of oxidative phosphorylation (chemiosmosis)?

|a. |36 |

|b. |77 |

|c. |173 |

|d. |212 |

|e. |1102 |

____ 72. Approximately what percentage of the energy of glucose (C6H12O6) is transferred to storage in ATP as a result of the complete oxidation of glucose to CO2 and water in cellular respiration?

|a. |2% |

|b. |4% |

|c. |10% |

|d. |25% |

|e. |40% |

____ 73. Recall that the complete oxidation of a mole of glucose releases 686 kcal of energy ([pic]G = -686 kcal/mol). The phosphorylation of ADP to form ATP stores approximately 7.3 kcal per mole of ATP. What is the approximate efficiency of cellular respiration for a "mutant" organism that produces only 29 moles of ATP for every mole of glucose oxidized, rather than the usual 36-38 moles of ATP?

|a. |0.4% |

|b. |25% |

|c. |30% |

|d. |40% |

|e. |60% |

____ 74. When glucose (C6H12O6) is oxidized to CO2 and water in cellular respiration, approximately 40% of the energy content of glucose is transferred to

|a. |the citric acid cycle. |

|b. |glycolysis. |

|c. |ATP (adenosine triphosphate). |

|d. |heat. |

|e. |oxygen (O2). |

____ 75. Which of the following normally occurs whether or not oxygen (O2) is present?

|a. |glycolysis |

|b. |fermentation |

|c. |oxidation of pyruvate to acetyl CoA |

|d. |citric acid cycle |

|e. |oxidative phosphorylation (chemiosmosis) |

____ 76. Which of the following occurs in the cytosol of the cell?

|a. |glycolysis and fermentation |

|b. |fermentation and chemiosmosis |

|c. |oxidation of pyruvate to acetyl CoA |

|d. |citric acid cycle |

|e. |oxidative phosphorylation |

____ 77. Fermentation takes place in the

|a. |cytosol. |

|b. |mitochondrial outer membrane. |

|c. |mitochondrial inner membrane. |

|d. |mitochondrial intermembrane space. |

|e. |mitochondrial matrix. |

____ 78. Which metabolic pathway is common to both cellular respiration and fermentation?

|a. |the oxidation of pyruvate to acetyl CoA |

|b. |the citric acid cycle |

|c. |oxidative phosphorylation |

|d. |glycolysis |

|e. |chemiosmosis |

____ 79. The ATP made during fermentation is generated by which of the following?

|a. |the electron transport chain |

|b. |substrate-level phosphorylation |

|c. |chemiosmosis |

|d. |oxidative phosphorylation |

|e. |aerobic respiration |

____ 80. Muscle cells in oxygen deprivation convert pyruvate to ____, and in this step gain____.

|a. |lactate; ATP |

|b. |alcohol; CO2 |

|c. |alcohol; ATP |

|d. |ATP; NADH2 |

|e. |lactate; NAD+ |

____ 81. In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of

|a. |ATP, CO2and ethanol (ethyl alcohol). |

|b. |ATP, CO2, and lactate. |

|c. |ATP, NADH, and pyruvate. |

|d. |ATP, pyruvate, and oxygen. |

|e. |ATP, pyruvate, and acetyl CoA. |

____ 82. In alcohol fermentation, NAD+ is regenerated from NADH during the

|a. |reduction of acetaldehyde to ethanol (ethyl alcohol). |

|b. |oxidation of pyruvate to acetyl CoA. |

|c. |reduction of pyruvate to form lactate. |

|d. |oxidation of NAD+ in the citric acid cycle. |

|e. |phosphorylation of ADP to form ATP. |

____ 83. The function of both alcohol fermentation and lactic acid fermentation is to

|a. |reduce NAD+ to NADH. |

|b. |reduce FAD+ to FADH2. |

|c. |oxidize NADH to NAD+. |

|d. |reduce FADH2 to FAD+. |

|e. |none of the above |

____ 84. Which of the following is not true concerning the cellular compartmentation of the steps of respiration or fermentation?

|a. |Acetyl CoA is produced only in the mitochondria. |

|b. |Lactate is produced only in the cytosol. |

|c. |NADH is produced only in the mitochondria. |

|d. |FADH2 is produced only in the mitochondria. |

|e. |ATP is produced in the cytosol and the mitochondria. |

____ 85. An organism is discovered that consumes a considerable amount of sugar, yet does not gain much weight when denied air. Curiously, the consumption of sugar increases as air is removed from the organism's environment, but the organism seems to thrive even in the absence of air. When returned to normal air, the organism does fine. Which of the following best describes the organism?

|a. |It must use a molecule other than oxygen to accept electrons from the electron transport chain. |

|b. |It is a normal eukaryotic organism. |

|c. |The organism obviously lacks the citric acid cycle and electron transport chain. |

|d. |It is an anaerobic organism. |

|e. |It is a facultative anaerobe. |

____ 86. Glycolysis is thought to be one of the most ancient of metabolic processes. Which statement supports this idea?

|a. |Glycolysis is the most widespread metabolic pathway. |

|b. |Glycolysis neither uses nor needs O2. |

|c. |Glycolysis is found in all eukaryotic cells. |

|d. |The enzymes of glycolysis are found in the cytosol rather than in a membrane-enclosed organelle. |

|e. |Ancient prokaryotic cells, the most primitive of cells, made extensive use of glycolysis long before oxygen was present |

| |in Earth's atmosphere. |

____ 87. Why is glycolysis considered to be one of the first metabolic pathways to have evolved?

|a. |It produces much less ATP than does oxidative phosphorylation. |

|b. |It is found in the cytosol, does not involve oxygen, and is present in most organisms. |

|c. |It is found in prokaryotic cells but not in eukaryotic cells. |

|d. |It relies on chemiosmosis which is a metabolic mechanism present only in the first cells-prokaryotic cells. |

|e. |It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells. |

____ 88. Molecules that can potentially be converted to intermediates of glycolysis and/or the citric acid cycle include

|a. |amino acids and proteins. |

|b. |glycerol and fatty acids. |

|c. |glucose and sucrose. |

|d. |starch and glycogen. |

|e. |all of the above |

____ 89. Which of the following organic molecules cannot be converted to an intermediate of glycolysis?

|a. |fatty acids |

|b. |amino acids |

|c. |glucose and sucrose |

|d. |glycerol |

|e. |starch and glycogen |

____ 90. Which of the following is not a true statement?

|a. |Glycerol can be converted to glyceraldehyde-3-phosphate, an intermediate of glycolysis. |

|b. |Beta oxidation breaks fatty acids down to two-carbon fragments that can enter the citric acid cycle as acetyl CoA. |

|c. |A gram of glucose oxidized by cellular respiration produces more than twice as much ATP as a gram of fat oxidized by |

| |cellular respiration. |

|d. |Proteins can be used as a fuel for cellular respiration, but their constituent amino acids must first be converted to |

| |intermediates of glycolysis or the citric acid cycle. |

|e. |Polysaccharides such as glycogen and starch are hydrolyzed to their constituent monosaccharides before they are used as |

| |fuel molecules for respiration. |

____ 91. You have a friend who lost 7 kg (about 15 pounds) of fat on a "low carb" diet. How did the fat leave her body?

|a. |It was released as CO2 and H2O. |

|b. |Chemical energy was converted to heat and then released. |

|c. |It was converted to ATP, which weighs much less than fat. |

|d. |It was broken down to amino acids and eliminated from the body. |

|e. |It was converted to urine and eliminated from the body. |

____ 92. Phosphofructokinase is an important control enzyme in the regulation of cellular respiration. Which of the following statements concerning phosphofructokinase is not true?

|a. |It is activated by AMP (derived from ADP). |

|b. |It is inhibited by ATP. |

|c. |It is activated by citrate, an intermediate of the citric acid cycle. |

|d. |It specifically catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, an early step of |

| |glycolysis. |

|e. |It is an allosteric enzyme. |

____ 93. Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount ATP in a cell would be expected to

|a. |inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle. |

|b. |activate the enzyme and thus slow the rates of glycolysis and the citric acid cycle. |

|c. |inhibit the enzyme and thus increase the rates of glycolysis and the citric acid cycle. |

|d. |activate the enzyme and increase the rates of glycolysis and the citric acid cycle. |

|e. |inhibit the enzyme and thus increase the rate of glycolysis and the concentration of citrate. |

____ 94. Organisms that can exist with light as an energy source and an inorganic form of carbon and other raw materials

|a. |are called photoautotrophs. |

|b. |do not exist in nature. |

|c. |are called heterotrophs. |

|d. |are best classified as decomposers. |

|e. |both C and D |

____ 95. Which type of organism obtains energy by metabolizing molecules produced by other organisms?

|a. |autotrophs |

|b. |heterotrophs |

|c. |decomposers |

|d. |B and C |

|e. |A, B, and C |

____ 96. The early suggestion that the oxygen (O2) liberated from plants during photosynthesis comes from water was

|a. |first proposed by C.B. van Niel of Stanford University. |

|b. |confirmed by experiments using oxygen-18 (18O). |

|c. |made following the discovery of photorespiration because of rubisco's sensitivity to oxygen. |

|d. |A and B |

|e. |A, B, and C |

____ 97. If photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (18O), later analysis will show that all but one of the following compounds produced by the algae contain the 18O label. That one exception is

|a. |PGA. |

|b. |PGAL. |

|c. |glucose. |

|d. |RuBP. |

|e. |O2. |

____ 98. Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

|a. |CO2 and glucose |

|b. |H2O and O2 |

|c. |ADP, Pi, and NADP+ |

|d. |electrons and H+ |

|e. |ATP and NADPH |

____ 99. What is the primary function of the light reactions of photosynthesis?

|a. |to produce energy-rich glucose from carbon dioxide and water |

|b. |to produce ATP and NADPH |

|c. |to produce NADPH used in respiration |

|d. |to convert light energy to the chemical energy of PGAL |

|e. |to use ATP to make glucose |

____ 100. What are the products of the light reactions that are subsequently used by the Calvin cycle?

|a. |oxygen and carbon dioxide |

|b. |carbon dioxide and RuBP |

|c. |water and carbon |

|d. |electrons and photons |

|e. |ATP and NADPH |

____ 101. Where does the Calvin cycle take place?

|a. |stroma of the chloroplast |

|b. |thylakoid membrane |

|c. |cytoplasm surrounding the chloroplast |

|d. |chlorophyll molecule |

|e. |outer membrane of the chloroplast |

____ 102. A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are not being absorbed by this pigment?

|a. |red and yellow |

|b. |blue and violet |

|c. |green and yellow |

|d. |blue, green, and red |

|e. |green, blue, and violet |

____ 103. During photosynthesis, visible light has enough energy to

|a. |force electrons closer to the nucleus. |

|b. |excite electrons. |

|c. |split a water molecule into hydrogen and oxygen. |

|d. |B and C only. |

|e. |A, B, and C. |

Use the following information to answer the questions below.

Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.

____ 104. What did Engelmann conclude about the congregation of bacteria in the red and blue areas?

|a. |Bacteria released excess carbon dioxide in these areas. |

|b. |Bacteria congregated in these areas due to an increase in the temperature of the red and blue light. |

|c. |Bacteria congregated in these areas because these areas had the most oxygen being released. |

|d. |Bacteria are attracted to red and blue light and thus these wavelengths are more reactive than other wavelengths. |

|e. |Bacteria congregated in these areas due to an increase in the temperature caused by an increase in photosynthesis. |

____ 105. An outcome of this experiment was to help determine

|a. |the relationship between heterotrophic and autotrophic organisms. |

|b. |the relationship between wavelengths of light and the rate of aerobic respiration. |

|c. |the relationship between wavelengths of light and the amount of heat released. |

|d. |the relationship between wavelengths of light and the oxygen released during photosynthesis. |

|e. |the relationship between the concentration of carbon dioxide and the rate of photosynthesis. |

____ 106. If you ran the same experiment without passing light through a prism, what would you predict?

|a. |There would be no difference in results. |

|b. |The bacteria would be relatively evenly distributed along the algal filaments. |

|c. |The number of bacteria present would decrease due to an increase in the carbon dioxide concentration. |

|d. |The number of bacteria present would increase due to an increase in the carbon dioxide concentration. |

|e. |The number of bacteria would decrease due to a decrease in the temperature of the water. |

____ 107. The figure below shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?

[pic]

|a. |Green and yellow wavelengths inhibit the absorption of red and blue wavelengths. |

|b. |Bright sunlight destroys photosynthetic pigments. |

|c. |Oxygen given off during photosynthesis interferes with the absorption of light. |

|d. |Other pigments absorb light in addition to chlorophyll a. |

|e. |Aerobic bacteria take up oxygen which changes the measurement of the rate of photosynthesis. |

____ 108. What wavelength of light is most effective in driving photosynthesis?

|a. |420 mm |

|b. |475 mm |

|c. |575 mm |

|d. |625 mm |

|e. |730 mm |

____ 109. In the thylakoid membranes, what is the main role of the antenna pigment molecules?

|a. |split water and release oxygen to the reaction-center chlorophyll |

|b. |harvest photons and transfer light energy to the reaction-center chlorophyll |

|c. |synthesize ATP from ADP and Pi |

|d. |transfer electrons to ferredoxin and then NADPH |

|e. |concentrate photons within the stroma |

____ 110. The reaction-center chlorophyll of photosystem I is known as P700 because

|a. |there are 700 chlorophyll molecules in the center. |

|b. |this pigment is best at absorbing light with a wavelength of 700 nm. |

|c. |there are 700 photosystem I components to each chloroplast. |

|d. |it absorbs 700 photons per microsecond. |

|e. |the plastoquinone reflects light with a wavelength of 700 nm. |

____ 111. All of the events listed below occur in the light reactions of photosynthesis except

|a. |oxygen is produced. |

|b. |NADP+ is reduced to NADPH. |

|c. |carbon dioxide is incorporated into PGA. |

|d. |ADP is phosphorylated to yield ATP. |

|e. |light is absorbed and funneled to reaction-center chlorophyll a. |

____ 112. Which of the following statements about the light reactions of photosynthesis are true?

|a. |The splitting of water molecules provides a source of electrons. |

|b. |Chlorophyll (and other pigments) absorb light energy, which excites electrons. |

|c. |ATP is generated by photophosphorylation. |

|d. |Only A and C are true. |

|e. |A, B, and C are true. |

____ 113. Which statement regarding events in the functioning of photosystem II is false?

|a. |Light energy excites electrons in an antenna pigment in a photosynthetic unit. |

|b. |The excitation is passed along to a molecule of P680 chlorophyll in the photosynthetic unit. |

|c. |The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+. |

|d. |The electron vacancies in P680 are filled by electrons derived from water. |

|e. |The splitting of water yields molecular oxygen as a by-product. |

____ 114. All of the following are directly associated with photosystem II except

|a. |extraction of hydrogen electrons from the splitting of water. |

|b. |release of oxygen. |

|c. |harvesting of light energy by chlorophyll. |

|d. |NADP+ reductase. |

|e. |P680 reaction-center chlorophyll. |

____ 115. All of the following are directly associated with photosystem I except

|a. |harvesting of light energy by chlorophyll. |

|b. |receiving electrons from plastocyanin. |

|c. |P700 reaction-center chlorophyll. |

|d. |extraction of hydrogen electrons from the splitting of water. |

|e. |passing electrons to ferredoxin. |

____ 116. Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be

|a. |to determine if they have thylakoids in the chloroplasts. |

|b. |to test for liberation of O2 in the light. |

|c. |to test for CO2 fixation in the dark. |

|d. |to do experiments to generate an action spectrum. |

|e. |to test for production of either sucrose or starch. |

____ 117. What are the products of noncyclic photophosphorylation?

|a. |heat and fluorescence |

|b. |ATP and P700 |

|c. |ATP and NADPH |

|d. |ADP and NADP |

|e. |P700 and P680 |

____ 118. What does cyclic electron flow in the chloroplast produce?

|a. |ATP |

|b. |NADPH |

|c. |glucose |

|d. |A and B |

|e. |A, B, and C |

____ 119. As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from?

|a. |photosystem II |

|b. |photosystem I |

|c. |cyclic electron flow |

|d. |noncyclic electron flow |

|e. |chlorophyll |

____ 120. Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?

|a. |the splitting of water |

|b. |the absorption of light energy by chlorophyll |

|c. |the flow of electrons from photosystem II to photosystem I |

|d. |the synthesis of ATP |

|e. |the reduction of NADP+ |

____ 121. What does the chemiosmotic process in chloroplasts involve?

|a. |establishment of a proton gradient |

|b. |diffusion of electrons through the thylakoid membrane |

|c. |reduction of water to produce ATP energy |

|d. |movement of water by osmosis into the thylakoid space from the stroma |

|e. |formation of glucose, using carbon dioxide, NADPH, and ATP |

____ 122. Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a pH-8 solution. What would be likely to happen?

|a. |The isolated chloroplasts will make ATP. |

|b. |The Calvin cycle will be activated. |

|c. |Cyclic photophosphorylation will occur. |

|d. |Only A and B will occur. |

|e. |A, B, and C will occur. |

____ 123. In a plant cell, where are the ATP synthase complexes located?

|a. |thylakoid membrane |

|b. |plasma membrane |

|c. |inner mitochondrial membrane |

|d. |A and C |

|e. |A, B, and C |

____ 124. In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from

|a. |the stroma to the photosystem II. |

|b. |the matrix to the stroma. |

|c. |the stroma to the thylakoid space. |

|d. |the intermembrane space to the matrix. |

|e. |ATP synthase to NADP+ reductase. |

____ 125. Which of the following statements best describes the relationship between photosynthesis and respiration?

|a. |Respiration is the reversal of the biochemical pathways of photosynthesis. |

|b. |Photosynthesis stores energy in complex organic molecules, while respiration releases it. |

|c. |Photosynthesis occurs only in plants and respiration occurs only in animals. |

|d. |ATP molecules are produced in photosynthesis and used up in respiration. |

|e. |Respiration is anabolic and photosynthesis is catabolic. |

____ 126. Where is the electron transport chain found in plant cells?

|a. |thylakoid membranes of chloroplasts |

|b. |stroma of chloroplasts |

|c. |inner membrane of mitochondria |

|d. |matrix of mitochondria |

|e. |cytoplasm |

____ 127. Of the following, what do both mitochondria and chloroplasts have in common?

|a. |thylakoid membranes |

|b. |chemiosmosis |

|c. |ATP synthase |

|d. |B and C only |

|e. |A, B, and C |

Refer to the choices to answer the following questions. Each choice may be used once, more than once, or not at all. Indicate whether the following events occur during

|A. |photosynthesis |

|B. |respiration |

|C. |both photosynthesis and respiration |

|D. |neither photosynthesis nor respiration |

____ 128. synthesis of ATP by the chemiosmotic mechanism

|a. |A |

|b. |B |

|c. |C |

|d. |D |

____ 129. reduction of oxygen which forms water

|a. |A |

|b. |B |

|c. |C |

|d. |D |

____ 130. reduction of NADP+

|a. |A |

|b. |B |

|c. |C |

|d. |D |

____ 131. the splitting of carbon dioxide to form oxygen gas and carbon compounds

|a. |A |

|b. |B |

|c. |C |

|d. |D |

____ 132. generation of proton gradients across membranes

|a. |A |

|b. |B |

|c. |C |

|d. |D |

____ 133. Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?

|a. |The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light |

| |reactions. |

|b. |The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the cycle provides water |

| |and electrons to the light reactions. |

|c. |The light reactions supply the Calvin cycle with CO2 to produce sugars, and the Calvin cycle supplies the light |

| |reactions with sugars to produce ATP. |

|d. |The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle provides the light |

| |reactions with water to split. |

|e. |There is no relationship between the light reactions and the Calvin cycle. |

____ 134. Where do the enzymatic reactions of the Calvin cycle take place?

|a. |stroma of the chloroplast |

|b. |thylakoid membranes |

|c. |outer membrane of the chloroplast |

|d. |electron transport chain |

|e. |thylakoid space |

____ 135. What is the primary function of the Calvin cycle?

|a. |use ATP to release carbon dioxide |

|b. |use NADPH to release carbon dioxide |

|c. |split water and release oxygen |

|d. |transport RuBP out of the chloroplast |

|e. |synthesize simple sugars from carbon dioxide |

____ 136. Which of the following is (are) required in the Calvin cycle?

|a. |CO2 |

|b. |ATP |

|c. |RuBP |

|d. |A and B only |

|e. |A, B, and C |

____ 137. Which statement is false?

|a. |Thylakoid membranes contain the photosynthetic pigments. |

|b. |The O2 released during photosynthesis comes from water. |

|c. |RuBP is produced during cyclic electron flow in the light reactions of photosynthesis. |

|d. |The light reactions of photosynthesis provide the energy for the Calvin cycle. |

|e. |When chlorophyll is reduced, it gains electrons. |

____ 138. One carbon dioxide molecule reacts in each "turn" of the Calvin cycle. How many turns of the cycle are required for the synthesis of one glucose molecule?

|a. |1 |

|b. |2 |

|c. |3 |

|d. |6 |

|e. |12 |

____ 139. All of the following statements are correct regarding the Calvin cycle except:

|a. |The energy source utilized is the ATP and NADPH obtained through the light reaction. |

|b. |These reactions begin soon after sundown and end before sunrise. |

|c. |The 5-carbon sugar RuBP is constantly being regenerated. |

|d. |One of the end products is glyceraldehyde phosphate. |

|e. |Rubisco attaches carbon dioxide to ribulose bisphosphate. |

For the following questions, compare the light reactions with the Calvin cycle of photosynthesis in plants. Use the following key:

|A. |light reactions alone |

|B. |the Calvin cycle alone |

|C. |both the light reactions and the Calvin cycle |

|D. |neither the light reactions nor the Calvin cycle |

|E. |occurs in the chloroplast but is not part of photosynthesis |

____ 140. produces molecular oxygen (O2)

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 141. requires ATP

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 142. produces NADH

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 143. produces NADPH

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 144. produces three-carbon sugars

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 145. requires CO2

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 146. requires glucose

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 147. inactive in the dark

|a. |A |

|b. |B |

|c. |C |

|d. |D |

|e. |E |

____ 148. Which of the following is (are) true of the enzyme ribulose bisphosphate carboxylase?

|a. |It participates in the Calvin cycle. |

|b. |It catalyzes a phosphorylation reaction. |

|c. |It has an affinity for both O2 and CO2. |

|d. |A and C are true. |

|e. |A, B, and C are true. |

____ 149. What are the substrates (normal reactants) for the enzyme RuBP carboxylase?

|a. |CO2 and O2 |

|b. |CO2 and glucose |

|c. |ATP and NADPH |

|d. |triose-P, glucose, and CO2 |

|e. |CO2 and ATP |

Use the figure below to answer the following statements.

[pic]

____ 150. Which of the following statements is true concerning the figure?

|a. |It represents cell processes involved in C4 photosynthesis. |

|b. |It represents the type of cell structures found in CAM plants. |

|c. |It represents an adaptation that minimizes photorespiration. |

|d. |A and C are true. |

|e. |A, B, and C are true. |

____ 151. Oxygen would inhibit the CO2 fixation reactions in

|a. |cell I only. |

|b. |cell II only. |

|c. |neither cell I nor cell II. |

|d. |both cell I and cell II. |

|e. |cell I during the night and cell II during the day. |

____ 152. In which cell would you expect photorespiration?

|a. |Cell I |

|b. |Cell II |

|c. |Cell I at night |

|d. |Cell II at night |

|e. |neither Cell I nor Cell II |

____ 153. In an experiment studying photosynthesis performed during the day, you provide a plant with radioactive carbon (14C) dioxide as a metabolic tracer. The 14C is incorporated first into oxaloacetate. The plant is best characterized as a

|a. |C4 plant. |

|b. |C3 plant. |

|c. |CAM plant. |

|d. |heterotroph. |

|e. |chemoautotroph. |

____ 154. Why are C4 plants able to photosynthesize with no apparent photorespiration?

|a. |They do not participate in the Calvin cycle. |

|b. |They use PEP carboxylase to initially fix CO2. |

|c. |They are adapted to cold, wet climates. |

|d. |They conserve water more efficiently. |

|e. |They exclude oxygen from their tissues. |

____ 155. CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they

|a. |fix CO2 into organic acids during the night. |

|b. |fix CO2 into sugars in the bundle-sheath cells. |

|c. |fix CO2 into pyruvate in the mesophyll cells. |

|d. |use the enzyme phosphofructokinase, which outcompetes rubisco for CO2. |

|e. |use photosystems I and II at night. |

____ 156. In C4 photosynthesis, carbon fixation takes place in the ____ cells, and then is transferred as malic or aspartic acid to ____ cells, where carbon dioxide is released for entry into the Calvin cycle.

|a. |mesophyll; bundle-sheath |

|b. |stomatal; mesophyll |

|c. |bundle-sheath; epidermal |

|d. |epidermal; mesophyll |

|e. |stomatal; epidermal |

____ 157. Photorespiration lowers the efficiency of photosynthesis by preventing the formation of

|a. |carbon dioxide molecules. |

|b. |3-phosphoglycerate molecules |

|c. |ATP molecules. |

|d. |ribulose bisphosphate molecules. |

|e. |RuBP carboxylase molecules. |

____ 158. Plants that fix CO2 into organic acids at night when the stomata are open and carry out the Calvin cycle during the day when the stomata are closed are called

|a. |C3 plants. |

|b. |C4 plants. |

|c. |CAM plants. |

|d. |B and C only. |

|e. |A, B, and C |

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