ch 8 mult choice

31. If an enzyme is saturated with substrate, the most effective way to obtain an even faster yield of products is to a. Add more of the enzyme. b. Heat the solution to 90-C or above. c. Add more substrate. d. Add an allosteric inhibitor. e. Add a noncompetitive inhibitor.

a

33. Glycolysis is believed to be one of the most ancient of metabolic processes. Which statement below least supports this idea? a. If run in reverse, glycolysis will build glucose molecules. b. Glycolysis neither used nor need free oxygen. 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. Bacteria, the most primitive of cells, make extensive use of glycolysis.

a

4. Which of the following is part of the first law of thermodynamics? a. Energy cannot be created or destroyed. b. The entropy of the universe is decreasing. c. The entropy of the universe is constant. d. Kinetic energy is stored energy that results from the specific arrangement of matter. e. Energy cannot be transferred or transformed.

a

42. During aerobic cellular respiration, a proton gradient in mitochondria will be generated by ________ and used primarily for ___________. a. The ETS ... ATP synthase b. The ETS ... substrate-level phosphorylation c. Glycolysis ... production of water d. Fermentation ... NAD reduction e. Diffusion of protons ... ATP synthesis

a

58. You have just lost 15 pounds on a diet. Where did all the fat go? a. It was released as CO2 and H2O b. It was converted to ATP, which weighs much less than fat c. It was broken down to amino acids and was eliminated from the body d. It was converted to urine and was eliminated from the body e. Aliens stole it for purposes of cloning

a

59. Organisms that can exist on light and an inorganic for of carbon and other raw materials a. Are called photoautotrophs (autotrophs) b. Do not exist in nature c. Are called heterotrophs d. Are classified as decomposers e. Both C and D

a

60. A new flower species has a unique photosynthetic pigment. The leaves of the 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

a

75. Which of the following statements best represents the relationships between the light reactions and the Calving 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 O2 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.

a

83. 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

a

85. In what respect are the photosynthetic adaptations of C4 plants and CAM plants similar? a. In both cases, the stomata normally close during the day. b. Both types of plants make their sugar without the Calvin cycle. c. In both cases, an enzyme other than rubisco carries out the first step in carbon fixation. d. Both types of plants make most of their sugar in the dark. e. Neither C4 plants nor CAM plants have grana in their chlorophasts.

a

86. The Calvin cycle takes place in the ___________ and the light reaction takes place in the _____________. a. stroma of the chloroplast .... thylakoid b. thylakoid ... stroma of the chloroplast c. cytoplasm surrounding the chloroplast ... mitochondria d. chlorophyll molecule ... PSII reaction center e. mitochondria ... nucleus

a

10. Which of the following statements is true concerning catabolic pathways? a. They combine molecules into more complex and energy-rich molecules. b. They are usually coupled with anabolic pathways to which they supply energy in the form of ATP. c. They involve endergonic reactions that break complex molecules into simpler ones. d. They are spontaneous and do not need enzyme catalysis. e. They build up complex molecules such as protein from simpler compounds.

b

15. The active site of an enzyme is the region that a. Binds with the allosteric site. b. Binds with the substrate. c. Binds with allosteric inhibitors. d. Is inhibited by a coenzyme or a cofactor. e. None of the above.

b

25. Location of an enzyme within a specific membrane-enclosed organelle a. Allows the use of ATP and cofactors by the enzyme. b. Brings order and promotes efficiency within eukaryotic cells. c. Allows cells to evolve by violating the second law of thermodynamics. d. Protects the enzyme from feedback inhibition. e. Is restricted to allosteric enzymes because it allows two polypeptide subunits to join efficiently.

b

40. During aerobic respiration, electrons travel downhill in which sequence? a. Food → Krebs cycle → ATP → NAD+ b. Food → NADH → ETS → oxygen c. Glucose → ATP → oxygen d. Glucose → ATP → ETS → NADH e. Food → glycolysis → Krebs cycle → NADH → ATP

b

45. The primary role of oxygen in respiration is to a. Yield energy in the form of ATP as it is pass down the respiratory chain b. Act as an acceptor for electrons and hydrogen, forming water c. Combine with carbon, forming CO2 d. Combine with lactic acid to form pyruvic acid e. Catalyze the glycolysis reaction

b

70. Some 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 dark 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

b

74. Which of the following statements best describes the relationship between photosynthesis and respiration? a. Respiration is the exact 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.

b

14. Which of these statements regarding enzymes is false? a. Enzymes are proteins that function as catalysts. b. Enzymes display specificity for certain molecules to which they attach. c. Enzymes provide activation energy for the reactions they catalyze. d. The activity of enzymes can be regulated by factors in their immediate environment. e. An enzyme may be used many times over for a specific reaction.

c

2. Which of the following is true regarding catabolic pathways? a. they do not depend of enzymes b. they consume energy to build up polymers from monomers c. they release energy as they degrade polymers to monomers d. they lead to the synthesis of catabolic compounds e. both A and B

c

32. some bacteria are metabolically active in hot springs because a. They are able to maintain an internal temperature much cooler than that of the surrounding water. b. The high temperatures facilitate active metabolism without the need of catalysis. c. Their enzymes have high optimal temperatures. d. Their enzymes are insensitive to temperature. e. They use molecules other than proteins as their main catalysts.

c

34. 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 oxidized it to NAD+. e. An agent that inhibits the formation of acetyl coenzyme A.

c

39. During oxidative phosphorylation, H2O is formed. Where do the oxygen atoms in the H2O come from? a. Carbon dioxide b. Glucose c. Molecular oxygen d. Pyruvate e. Lactate

c

46. 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 TES b. Protons pumps embedded in the inner membrane c. Enzymes for glycolysis d. Enzymes for the Krebs cycle e. Mitochondrial ATP synthase

c

72. As a research scientist, you measure the amount of ATP and HADPH 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

c

84. Plants that fix CO2 into organic acids at night when the stoma are open and carry out the Calving cycle during the day when the stoma are closed are called a. C3 plants b. C4 plants c. CAM plants d. A and B e. A, B, C

c

9. ATP generally energizes a cellular process by a. Releasing heat upon hydrolysis b. Acting as a catalyst c. Direct chemical transfer of a phosphate group d. Releasing ribose electrons to drive reactions e. Emitting light flashes

c

22. Zinc, an essential trace element, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n) a. Competitive inhibitor of the enzyme. b. Noncompetitive inhibitor of the enzyme. c. Allosteric activator of the enzyme. d. Cofactor necessary for enzyme activity. e. Coenzyme derived from a vitamin.

d

41. 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 ETS 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

d

43. 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 ETS 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 Krebs cycle intermediate molecules of ADP

d

44. When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is a. The formation of ATP b. The reduction of NAD+ c. The restoration of the Na+-K+ balance across the membrane d. The creation of a proton gradient e. The lowering of pH in the mitochondrial matrix

d

61. The color of light least effective in driving photosynthesis is a. Blue b. Red c. Orange d. Green e. Yellow

d

62. Refer to the figure. The figure shows the absorption spectrum of chlorophyll a and the action spectrum for photosynthesis. Why are they different? a. Green and yellow wavelengths inhibit the absorption of red and blue wavelengths. b. Bright sunlight destroys photosynthetic pigments. c. The two lines are probably the result of inaccurate measurements. d. Other pigments absorb light in addition to chlorophyll a. e. Anaerobic bacteria probably interfered with light absorption.

d

64. The following statements about the light reactions of photosynthesis are all true except 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. RUBP carboxylase is activated by photons e. Electrons are transferred from water to NADP+

d

66. Because bundle-sheath cells are relatively protected from atmospheric oxygen, the level of _________ is held to a minimum in C4 plants. a. Glycolysis b. Photosynthesis c. Oxidative phosphorylation d. Photorespiration e. Decarboxylation of malic acid

d

73. (Bonus) Assume a thylakoid is somehow punctured so that the interior of the thylakoid is not longer separated for 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 PSII to PSI d. The synthesis of ATP e. The reduction of NADP+

d

21. Which of the following is true of enzymes? a. Enzymes may require a nonprotein cofactor or ion for catalysis to take place. b. Enzyme function is reduced if the three-dimensional structure or conformation of an enzyme is altered. c. Enzyme function is influenced by physical and chemical environment factors such as pH and temperature. d. Enzymes increase the rate of chemical reaction by lowering activation energy barriers. e. All of the above are true.

e

3. Anabolic pathways a. do not depend on enzymes b. depend on enzymes c. consume energy to build up polymers from monomers d. release energy as they degrade polymers to monomers e. both B and C

e

36. All of the following are function of the Krebs cycle except a. Production of ATP. b. Production of NADH. c. Production of FADH2. d. Release of CO2. e. Adding electrons and protons to oxygen to form water.

e

47. How many moles of ATP are produced from the complete oxidation of a mole of glucose in cellular respiration? a. 12 b. 15 c. 20 d. 30 e. 36

e

56. Carbon skeletons to be broken down during cellular respiration can be obtained from a. Polysaccharides b. Proteins c. Lipids d. A and B e. A, B, C

e

6. What is the change in free energy at chemical equilibrium? a. Slightly increasing b. Greatly increasing c. Slightly decreasing d. Greatly decreasing e. There is no net change

e

69. What are the products of the light reactions that are subsequently used by the Calvin cycle? a. O2 and CO2 b. CO2 and RuBP c. Water and carbon d. Electrons and photons e. ATP and NADPH

e

53. Which of the following statements is true of fermentation? a. It produces a net gain of ATP b. It produces a net gain of NADH c. It is an aerobic process d. It can be performed only by bacteria e. It produces more energy per glucose molecule than does aerobic respiration

a

54. What must a muscle cell do to keep contracting? a. Regenerate ATP at a very fast rate. b. Receive sufficient oxygen for glycolysis. c. Store sufficient ATP as a raw material for oxidative phosphorylation. d. Rapidly replace the enzymes of respiration. e. Effectively transport NADH into the mitochondria

a

8. A chemical reaction that has a positive ΔG is correctly described as a. Endergonic b. Exergonic c. Enthalpic d. Spontaneous e. Exothermic

a

13. How does an enzyme catalyze a reaction? a. By supplying the energy to speed up a reaction. b. By lowering the energy of activation of a reaction. c. By lowering the free energy of a reaction. d. By changing the equilibrium of a spontaneous reaction. e. By increasing the amount of free energy of a reaction.

b

65. What is the primary function of the light reactions of photosynthesis? a. To produce energy-rich glucose from CO2 and H2O b. To produce ATP, NADPH, and O2 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

b

7. Which of the following is true for exergonic reactions? a. The products have more free energy than the reactants. b. The products have less free energy than the reactants. c. Reactants will always be completely converted to products. d. A net input of energy from the surroundings is required for the reactions to proceed. e. The reactions upgrade the free energy in the products at the expense of energy from the surroundings.

b

20. Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? a. Denaturization of the enzyme b. Allosteric inhibition c. Competitive inhibition d. Noncompetitive inhibition e. Insufficient cofactors

c

35. In addition to ATP, what are the end products of glycolysis? a. CO2 and H2O b. CO2 and ethyl alcohol c. NADH and pyruvate d. CO2 and NADH e. H2O and ethyl alcohol

c

5. Which of the following is the most randomized form of energy? a. Light energy b. Electrical energy c. Thermal energy d. Mechanical energy e. Chemical potential energy

c

63. All of the events listed below occur in the energy-capturing 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

c

11. How can one increase the rate of a chemical reaction? a. Increase the activation energy needed. b. Cool the reactants. c. Decrease the concentration of reactants. d. Add a catalyst. e. Increase the entropy of reactants.

d

57. Which of the following does not participate in glycolysis? a. Fatty acids b. Sucrose c. Glucose d. Glycerol e. Starch

d

1. Metabolism is best described as a. synthesis of macromolecules b. breakdown of macromolecules c. control of enzyme activity d. A and B e. A, B, C

e

67. All of the following are directly associated with photosystem II except a. Photolysis b. Release of O2 c. Harvesting of light energy by chlorophyll d. Photophosphorylation e. P680

...

68. 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 d. Photolysis e. Passing electrons to ferredoxin

...