Lodish 8e Ch12 Test Bank PDF

lOMoARcPSD|46169929 Lodish 8e Ch12 Test Bank Cell biology (Yonsei University) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by girasol rey ([email protected]) ...

lOMoARcPSD|46169929 Lodish 8e Ch12 Test Bank Cell biology (Yonsei University) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 1 12 Section 12.1 Cellular Energetics 1. _____ is the carbon-containing compound produced by glycolysis. a. Pyruvate b. Glucose c. CO2 d. Acetyl CoA Ans: a Question Type: Multiple choice Section 12.1 Blooms: Remembering Difficulty: Easy 2. In the glycolytic pathway, which of the following are allosterically controlled enzymes? a. triose phosphate isomerase b. phosphofructokinase-1 c. enolase d. none of the above Ans: b. Question Type: Multiple choice Section 12.1 Blooms: Understanding Difficulty: Easy 3. Yeasts use fermentation to synthesize ATP: a. in the absence of oxygen. b. because fermentation produces more ATP than oxidative phosphorylation. c. because yeasts lack mitochondria. d. to produce lactic acid. Ans: a Question Type: Multiple choice Section 12.1 Blooms: Understanding Difficulty: Moderate 4. What is the role of substrate-level phosphorylation in glycolysis? Ans: During glycolysis, substrate level phosphorylation is used to synthesize ATP. This process occurs twice during glycolysis and involves the transfer of a high-energy phosphate group (from 1,3-bisphosphate or phosphoenolpyruvate) to ADP. Question Type: Essay Section 12.1 Applying Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 2 Difficulty: Moderate 5. During prolonged exercise, oxygen is scarce in muscle tissue. Under these conditions, muscle cells convert pyruvate to two molecules of lactic acid. What happens to the lactic acid that is generated in this way? Ans: Lactic acid is secreted from muscle cells into the bloodstream. Some is taken up from the bloodstream by the liver, where it is either reoxidized to pyruvate then metabolized to generate energy and CO2 or it is converted back to glucose and stored as glycogen in the liver. Some of the lactic acid is metabolized to CO2 in the heart. Question Type: Essay Section 12.1 Applying Difficulty: Difficult 6. In the overall reaction for cellular respiration, glucose is: a. oxidized to CO2. b. reduced to CO2. c. oxidized to O2. d. reduced to O2. Ans: a Question Type: Multiple choice Section 12.1 Blooms: Remembering Difficulty: Easy 7. Phosphofructokinase is _____ active in the glycolytic pathway when the levels of ATP are high in the cell because _____. a. less; ATP is an allosteric inhibitor b. less; ATP is a competitive inhibitor c: more; ATP stimulates phosphofructokinase through allosteric interactions d. more; lower ADP levels activate phosphofructokinase Ans: a Question Type: Multiple choice Section 12.1 Blooms: Remembering Difficulty: Easy 8. In the absence of oxygen, NAD+ is recovered by _____, which leads to a net production of _____ ATP molecules for each glucose molecule broken down. a. fermentation; two b. fermentation; four c. aerobic respiration; two d. anabolism; four Ans: a Question Type: Multiple choice Section 12.1 Blooms: Remembering Difficulty: Easy Section 12.2 9. Which of the following is FALSE regarding mitochondrial structure? a. The inner mitochondrial membrane contains more surface area than the outer membrane and contains many of the proteins required for making ATP. Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 3 b. The outer mitochondrial membrane contacts the cellular cytosol and the mitochondrial matrix. c. Mitochondria contain DNA in the matrix. d. The curved morphology of cristae are due to MICOS protein complexes. Ans: b Question Type: Multiple choice Section 12.2 Blooms: Understanding Difficulty: Moderate 10. Which of the following health-related conditions are NOT related to mitochondrial function? a. Tay-Sachs disease b. Parkinson’s disease c. Kearns-Sayre syndrome d. aging Ans: a Question Type: Multiple choice Section 12.2 Blooms: Remembering Difficulty: Moderate Section 12.3 11. Electron transport from NADH and FADH2 to O2 occurs in the: a. mitochondrial matrix. b. cytosol. c. mitochondrial inner membrane. d. mitochondrial outer membrane. Ans: c Question Type: Multiple choice Section 12.3 Blooms: Remembering Difficulty: Easy 12. Compared with glucose, oxidation of which of the following is more important in humans as a source of ATP? a. cellulose b. sucrose c. proteins d. fats Ans: d Question Type: Multiple choice Section 12.3 Blooms: Understanding Difficulty: Easy 13. The four stages of glucose oxidation are listed below. Place them in the correct order. I. pyruvate oxidation to CO2 in the mitochondrion via a 2-carbon acetyl CoA intermediate (citric acid cycle) II. electron transport to generate a proton motive force III. conversion in the cytosol of one 6-carbon glucose molecule to two 3-carbon pyruvate molecules (pyruvate) (glycolysis) IV. ATP synthesis in the mitochondrion (oxidative phosphorylation) Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 4 a. I, II, III, IV b. II, III, I, IV c. III, II, IV, I d. III, I, II, IV Ans: d Question Type: Multiple choice Section 12.3 Applying Difficulty: Moderate 14. What is the function of the malate–aspartate shuttle? Ans: The malate–aspartate shuttle functions to deliver the electrons produced during glycolysis and carried by cytosolic NADH across the mitochondrial inner membrane to the matrix, where the electrons serve to reduce NAD + to NADH in the matrix. This NADH in the matrix can then donate electrons to the electron transport chain. Question Type: Essay Section 12.3 Applying Difficulty: Difficult 15. The molecule that immediately enters the citric acid cycle is formed by which process? a. chemiosmosis b. glycolysis c. the light reactions d. pyruvate conversion Ans: d Question Type: Multiple choice Section 12.3 Blooms: Remembering Difficulty: Easy 16. The first step in the citric acid cycle occurs when acetyl CoA reacts with oxaloacetate to form: a. succinate. b. citrate. c. pyruvate d. cytochrome c Ans: b Question Type: Multiple choice Section 12.3 Blooms: Remembering Difficulty: Easy 17. Glucose is not the only energy-containing molecule that can enter cellular respiration pathways. Which food source is most likely to enter the citric acid cycle as fatty acids? a. fats b. carbohydrates c. amino acids d. DNA Ans: a Question Type: Multiple choice Section 12.3 Blooms: Understanding Difficulty: Easy Section 12.4 Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 5 18. NADH-CoQ reductase and CoQH2–cytochrome c reductase each use the energy derived from electron transfer to transport _____ the mitochondrial matrix. a. four protons into b. two protons into c. four protons out of d. two protons out of Ans: a Question Type: Multiple choice Section 12.4 Blooms: Remembering Difficulty: Easy 19. _____ is a lipid soluble molecule that acts to shuttle electrons within the mitochondrial inner membrane. a. Cytochrome c b. NADH c. CoQ d. FADH2 Ans: c Question Type: Multiple choice Section 12.4 Blooms: Remembering Difficulty: Easy 20. In mitochondria, the proton-motive force is due largely to: a. a voltage gradient across the outer membrane. b. a voltage gradient across the inner membrane. c. a pH gradient across the outer membrane. d. a pH gradient across the inner membrane. Ans: b Question Type: Multiple choice Section 12.4 Blooms: Understanding Difficulty: Moderate 21. Each cytochrome in the electron transport chain has a different reduction potential. What is the importance of these differences for electron transport? Ans: The different reduction potential (or tendency to accept an electron) of the cytochromes in the electron transport chain allows these molecules to establish a unidirectional electron flow along the chain. Question Type: Essay Section 12.4 Blooms: Understanding Difficulty: Moderate Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 6 22. During cellular respiration, the electron transport chain utilizes the energy produced from passing electrons from one molecule to the next to create: a. a proton gradient. b. NADH. c. CO2. d. an electron gradient. Ans: b Question Type: Multiple choice Section 12.4 Blooms: Understanding Difficulty: Easy Section 12.5 23. Which of the following statement(s) regarding the origin of the mitochondria is(are) TRUE? a. A bacterium invaded and established a symbiotic relationship with a eukaryotic host cell. b. The outer mitochondrial membrane is derived from the bacterial plasma membrane. c. The globular F1 domain points toward the mitochondria’s intermembrane space. d. all of the above Ans: a Question Type: Multiple choice Section 12.5 Blooms: Understanding Difficulty: Moderate 24. During ATP synthesis, protons move “down” their electrochemical gradient through: a. the F0 complex of ATP synthase. b. the F1 complex of ATP synthase. c. a proton channel protein. d. CoQH2–cytochrome c reductase. Ans: a Question Type: Multiple choice Section 12.5 Blooms: Remembering Difficulty: Easy 25. Transport of pyruvate into the mitochondrial matrix depends on energy provided by: a. ATP hydrolysis. b. ATP synthesis. c. a Na+ gradient. d. the proton-motive force. Ans: d Question Type: Multiple choice Section 12.5 Blooms: Remembering Difficulty: Easy 26. Brown-fat mitochondria uncouple oxidative phosphorylation to produce: a. ADP. b. oxygen. c. heat. d. fat. Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 7 Ans: c Question Type: Multiple choice Section 12.5 Blooms: Remembering Difficulty: Easy 27. A major source of reactive oxygen species (ROS) in animal cells is: a. glycolysis. b. electron transport in the mitochondria. c. the reactions catalyzed by catalase and glutathione peroxidase. d. vitamin E and  lipoic acid. Ans: b Question Type: Multiple choice Section 12.5 Blooms: Understanding Difficulty: Easy 28. ATP synthase is composed of two oligomeric proteins, F0 and F1. What is the function of each protein complex and where is each found in mitochondria? Ans: F0 is a proton-channel protein and the F1 complex is an ATPase running in reverse. F0 is found in the mitochondrial inner membrane and F1 is associated with F0 on the matrix face of the inner membrane. Question Type: Essay Section 12.5 Applying Difficulty: Moderate Section 12.6 29. In chloroplasts, light absorption, electron transport, and ATP synthesis all occur: a. in the stroma. b. in the thylakoid lumen. c. in or on the thylakoid membrane. d. in or on the inner membrane. Ans: c Question Type: Multiple choice Section 12.6 Blooms: Understanding Difficulty: Moderate 30. The principal pigment involved in photosynthesis is: a. carotenoid. b. chlorophyll a. c. chlorophyll b. d. heme. Ans: b Question Type: Multiple choice Section 12.6 Blooms: Remembering Difficulty: Easy Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 8 31. In photosynthesis, all of the following reactions are directly dependent on light, except: a. carbon fixation. b. synthesis of ATP. c. electron transport. d. removal of electrons from H2O. Ans: a Question Type: Multiple choice Section 12.6 Applying Difficulty: Moderate 32. Which stages of photosynthesis can occur only in the light and which can also occur in the dark? Ans: Of the four stages of photosynthesis, the first three (light absorption, electron transport, and ATP synthesis) can occur only when light is available. The last stage, carbon fixation, can occur whether or not light is available. Although carbon fixation can take place in the dark, the reactions involved are often turned off in the dark to conserve ATP for other cellular processes. Question Type: Essay Section 12.6 Blooms: Understanding Difficulty: Moderate 33. What is the role of quinone in generating the charge separation needed to remove electrons from H 2O for use in electron transport? Ans: Quinone Q is a strong reducing agent and accepts an electron from reaction-center chlorophyll when this chlorophyll is in a photon-induced excited state. This leaves the reaction-center chlorophyll in a strong oxidizing state that is powerful enough to remove electrons from H2O. Question Type: Essay Section 12.6 Blooms: Understanding Difficulty: Difficult Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 9 34. Based on what you know about the action spectra of photosynthesis, irradiating a leaf with which of the following light types would result in the release of the greatest quantities of oxygen? a. red and orange light b. red and blue light c. green and blue light d. violet and yellow light Ans: b Question Type: Multiple choice Section 12.6 Applying Difficulty: Easy 35. The "tail" of chlorophyll is hydrophobic, which is important for: a. absorbing blue light. b. anchoring it in the thylakoid membrane. c. transferring electrons. d. giving plants their green color. Ans: b Question Type: Multiple choice Section 12.6 Blooms: Understanding Difficulty: Moderate 36. Plastoquinone, like ubiquinone, can move freely within the membrane. This is important for its function as: a. an electron and proton shuttle. b. an electron carrier. c. a reaction center. d. a pump. Ans: a Question Type: Multiple choice Section 12.6 Blooms: Understanding Difficulty: Moderate 37. What is the role of water in the light reactions of photosynthesis? a. provides energy b. accepts electrons c. accepts protons d. source of electrons Ans: d Question Type: Multiple choice Section 12.6 Blooms: Understanding Difficulty: Easy 38. Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from: a. water. b. air. c. electrons from NADPH. d. glucose. Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 10 Ans: a Question Type: Multiple choice Secion 12.6 Blooms: Understanding Difficulty: Easy Section 12.7 39. Cyclic electron flow in the thylakoid membrane generates: a. oxygen. b. a proton-motive force. c. sulfur. d. NADPH. Ans: b Question Type: Multiple choice Section 12.7 Blooms: Understanding Difficulty: Easy 40. During photosynthesis, O2 is produced: a. on the stromal face of the thylakoid membrane. b. on the luminal face of the thylakoid membrane. c. throughout the stromal space. d. throughout the entire chloroplast. Ans: b Question Type: Multiple choice Section 12.7 Blooms: Understanding Difficulty: Easy 41. During cyclic electron flow, electron transport: a. involves neither PSI nor PSII. b. takes place only in PSI. c. takes place only in PSII. d. cycles electrons back and forth between PSI and PSII. Ans: b Question Type: Multiple choice Section 12.7 Blooms: Understanding Difficulty: Moderate 42. All of the following statements describe the process of photorespiration, except: a. photorespiration consumes O2. b. photorespiration generates CO2. c. photorespiration generates substantial amounts of ATP. d. photorespiration competes with photosynthesis. Ans: c Question Type: Multiple choice Section 12.7 Applying Difficulty: Moderate Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 11 43. What molecule acts as an electron donor during photosynthesis in chloroplasts? What alternative is used by some photosynthetic bacteria (e.g., purple bacteria)? Ans: H2O is the electron donor during photosynthesis in chloroplasts, whereas some photosynthetic bacteria (e.g., purple bacteria) can use H2S or H2 as an electron donor. Question Type: Essay Section 12.7 Blooms: Understanding Difficulty: Moderate 44. Which components of PSII are responsible for producing the proton-motive force? Ans: Several components of PSII contribute to the proton-motive force, albeit by different mechanisms. First, the removal of electrons from water by P680 generates protons in the thylakoid space. Next, the delivery of electrons by quinone Q to cytochrome bf is accompanied by the transfer of two protons from the stroma to the thylakoid lumen. Finally, protons may be transported from the stroma to the thylakoid space by cytochrome bf functioning in a Q cycle. Question Type: Essay Section 12.7 Blooms: Understanding Difficulty: Difficult Section 12.8 45. The enzymes that catalyze the Calvin cycle are found in the: a. thylakoid lumen. b. phloem. c. cytosol. d. stromal space. Ans: d Question Type: Multiple choice Section 12.8 Blooms: Remembering Difficulty: Easy 46. The fixation of CO2 into carbohydrates is catalyzed by: a. ribulose 1,5-bisphosphate carboxylase. b. thioredoxin. c. rubisco activase. d. 3-phosphoglycerate. Ans: a Question Type: Multiple choice Section 12.8 Blooms: Remembering Difficulty: Easy 47. Plants use _____ to transport sucrose to all regions of the organism. a. the xylem b. the phloem c. mesophyll cells d. root cells Ans: b Question Type: Multiple choice Section 12.8 Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 12 Blooms: Remembering Difficulty: Easy 48. What is the source of the energy for carbon fixation? Ans: The reactions that fix CO2 are powered by energy released by ATP hydrolysis and by the reducing agent NADPH. The ATP and NADPH were previously generated from the energy of absorbed photons of light. Question Type: Essay Section 12.8 Blooms: Understanding Difficulty: Moderate 49. What is photorespiration? How is it related to photosynthesis? Ans: Photorespiration competes with the process of photosynthesis. During photorespiration, O 2 and ATP are consumed and CO2 is generated. Rubisco, which acts to fix CO2, also catalyzes photorespiration. Photorespiration is favored when stomata close to prevent moisture loss, and CO2 levels inside the leaf fall below the Km of rubisco for CO2. Question Type: Essay Section 12.8 Blooms: Understanding Difficulty: Moderate 50. Explain how the rates of photosynthesis in plants like corn and sugarcane can be two to three times faster than the rates of photosynthesis in plants like wheat or rice. Ans: Sugarcane and corn are C4 plants, whereas wheat and rice are C3 plants. C4 plants have evolved a two-step system that reduces the rate of photorespiration and enhances the rate of photosynthesis. This system works via a CO2 shuttle that involves binding CO2 in mesophyll cells. The carbon dioxide is stored in the oxaloacetate. Oxaloacetate is a four-carbon molecule that gives the C4 plants their name. Oxaloacetate is converted to malate, which is transferred to bundle cells. Malate reacts to release CO2 in the bundle cells. This increases the CO2 concentration in bundle cells and, as a result, increases the rate of photosynthesis. Question Type: Essay Section 12.8 Applying Difficulty: Difficult Downloaded by girasol rey ([email protected])  lOMoARcPSD|46169929 12 - 13 51. Why doesn't the Calvin cycle end after a three-carbon sugar is produced? a. because electrons are still excited in the photosystems b. because O2 must be produced to act as a final electron acceptor c. because RuBP must be generated for the cycle to continue d. because there are not enough carbon building blocks in the cell Ans: c Question Type: Multiple choice Section 12.8 Blooms: Understanding Difficulty: Easy 52. The Calvin cycle: a. converts glucose into energy in the form of NADH and ATP. b. uses glucose and electrons from NADPH to make ATP. c. uses ATP and glucose to make NADPH. d. uses electrons from NADPH and ATP to produce glucose. Ans: d Question Type: Multiple choice Section 12.8 Blooms: Understanding Difficulty: Easy Downloaded by girasol rey ([email protected])