OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Chapter 8: Microbial Metabolism * = Correct answer | 2022 update

OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Chapter 8: Microbial Metabolism * = Correct answer Multiple Choice 1. Which of the following refers to the term metabolism? A. all the reactions in a cell or organism* B. all the reactions in a cell that break down molecules only C. all the reactions in a cell that build new molecules only D. all the reactions in a cell that decompose molecules only Difficulty: Easy ASM Standard: N/A 2. Which of the following best describes an endergonic reaction? A. absorbs energy from the environment* B. is coupled with another reaction C. is involved in biosynthesis D. releases energy into the environment Difficulty: Easy ASM Standard: N/A 3. Chemotrophs obtain their energy from which of the following? A. inorganic chemical reactions only B. light energy C. organic chemical reactions only D. organic and inorganic chemical reactions* Difficulty: Easy ASM Standard: 11 4. Which of the following describes a molecule that had an electron removed? A. anabolized B. electronated C. oxidized* D. reduced Difficulty: Easy ASM Standard: N/A 5. Which of the following best describes the subcomponents of pyrophosphate? A. two inorganic phosphate molecules* B. two organic phosphate molecules C. three inorganic phosphate molecules Page 1 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism D. three organic phosphate molecules Difficulty: Easy ASM Standard: N/A 6. Which molecule is often called the cell’s energy currency? A. adenosine triphosphate* B. flavin adenine dinucleotide C. nicotinamide adenine dinucleotide D. nicotinamide adenine dinucleotide phosphate Difficulty: Easy ASM Standard: N/A 7. Which site on an enzyme is where substrates bind? A. the activation site B. the active site* C. the catalyst site D. the lock and key site Difficulty: Easy ASM Standard: N/A 8. Which of the following are inorganic molecules that bind to enzymes? A. apoenzymes B. coenzymes C. cofactors* D. holoenzymes Difficulty: Easy ASM Standard: N/A 9. Which of the following best describes catabolic pathways? A. They always absorb energy. B. They break down large molecules into smaller components.* C. They build up large molecules from smaller components. D. They must be coupled with the breakdown of ATP. Difficulty: Moderate ASM Standard: N/A 10. Which group comprises all lithotrophs? A. algae B. autotrophs C. microbes* D. plants Page 2 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Difficulty: Moderate ASM Standard: 11, 20, 22 11. Which is a common electron acceptor in catabolic reactions? A. ATP B. FADH2 C. NAD+ * D. NADPH Difficulty: Moderate ASM Standard: N/A 12. The reaction that breaks down ATP to form ADP and inorganic phosphate is classified as which of the following? A. endergonic B. exergonic* C. nonspontaneous D. reduction Difficulty: Moderate ASM Standard: N/A 13. Which of the following is an inhibitor that binds to the active site of an enzyme? A. a competitive inhibitor* B. a noncompetitive inhibitor C. an allosteric inhibitor D. an uncompetitive inhibitor Difficulty: Moderate ASM Standard: N/A 14. Glycolysis produces a net gain of which of the following? A. two ATP, two NADH, and two pyruvates* B. two ATP, two NADH, and four pyruvates C. two ATP, four NADH, and two pyruvates D. four ATP, two NADH, and two pyruvates Difficulty: Easy ASM Standard: N/A 15. Which of the following is a pathway that breaks down glucose in some microbes? A. the Calvin cycle B. the Entner-Doudoroff pathway* C. the Krebs cycle D. the tricarboxylic acid cycle Page 3 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Difficulty: Moderate ASM Standard: 11, 22 16. Which of the following best describes a transition reaction? A. a reaction that converts pyruvate to acetyl CoA with the release of carbon dioxide* B. a series of reactions that convert citric acid to oxaloacetate C. an optional reaction that transports pyruvate into the mitochondrion D. the reaction that converts glucose to glucose-6-phosphate in glycolysis Difficulty: Moderate ASM Standard: N/A 17. Which of the following is not a product of the Krebs cycle? A. carbon dioxide B. GTP, which is converted to ATP C. NADH D. pyruvate* Difficulty: Moderate ASM Standard: 20, 22 18. The Krebs cycle begins with the addition of acetyl CoA to which of the following? A. citric acid B. oxaloacetate* C. ribulose bisphosphate D. succinate dehydrogenase Difficulty: Moderate ASM Standard: NA 19. Which of the following is the step in which CO2 enters the light-independent reactions (Calvin cycle)? A. fixation* B. reduction C. regeneration D. transition Difficulty: Moderate ASM Standard: 20, 22 20. Carotenoids are pigments that are which of the following colors? A. blue/green B. green/orange C. orange/yellow/red* D. purple/blue Page 4 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Difficulty: Moderate ASM Standard: N/A 21. Which of the following are enzymes that break down proteins? A. amylases B. oxidases C. oxygenases D. proteases* Difficulty: Easy ASM Standard: N/A 22. Fatty acids are often degraded using which set of reactions? A. β-oxidation* B. glycolysis C. photophosphorylation D. the tricarboxylic acid cycle Difficulty: Moderate ASM Standard: N/A 23. Triglycerides are broken down by which of the following? A. lipases* B. nitrogenases C. phospholipases D. proteases Difficulty: Moderate ASM Standard: N/A 24. During the Krebs cycle, FAD is reduced to which of the following? A. FADH B. FADH2* C. NADH D. NADH2 Difficulty: Moderate ASM Standard: N/A 25. Which of the following is the purpose of fermentation? A. to produce carbon dioxide B. to produce large quantities of additional energy C. to regenerate NAD+ * D. to regenerate oxygen Page 5 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Difficulty: Moderate ASM Standard: 11, 20, 22 26. ATP is produced through oxidative phosphorylation when which of the following occurs? A. FADH2 donates electrons to succinate dehydrogenase B. H + moves through ATP synthase* C. NADH donates electrons to NADH dehydrogenase D. the light-independent reactions fix CO2 Difficulty: Moderate ASM Standard: N/A 27. Each pyruvate molecule contains how many carbon atoms? A. two B. three* C. four D. six Difficulty: Moderate ASM Standard: N/A 28. When is the pentose phosphate pathway favored over other pathways to break down glucose? A. when biosynthesis is not needed B. when phospholipids are needed D. when the cell has a severe energy deficit and needs energy rapidly C. when the synthesis of nucleic acids and proteins is needed* Difficulty: Difficult ASM Standard: 11, 22 29. Which of the following occurs when molecules are broken down using β-oxidation? A. Carbon dioxide is removed. B. Three carbon propyl groups are removed. C. Two carbon acetyl groups are removed.* D. Two carbon acyl groups are removed. Difficulty: Difficult ASM Standard: N/A 30. Which of the following best defines chemiosmosis? A. the disruption of the inner mitochondrial membrane, which dissipates energy B. the movement of electrons from one acceptor to another C. the movement of hydrogen ions through ATP synthase* D. the series of reactions that regenerate oxaloacetate Page 6 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Difficulty: Difficult ASM Standard: N/A 31. Which of the following is the most acidic location in a mitochondrion? A. the intermembrane space* B. the matrix C. within the outer membrane D. within the thylakoid Difficulty: Difficult ASM Standard: N/A 32. Which of the following is not a common electron acceptor in anaerobic respiration? A. Fe3 + B. H2S C. NO3 – D. PO4 3–* Difficulty: Difficult ASM Standard: N/A 33. Why is the actual ATP yield of aerobic respiration often less than the maximum possible yield of 38 ATP? A. Aerobic respiration competes with anaerobic respiration for energy. B. Aerobic respiration competes with fermentation for energy. C. In eukaryotes, energy is used to move molecules across membranes. D. No organisms complete all parts of aerobic respiration. Difficulty: Difficult ASM Standard: N/A 34. How can enteropathogenic O157:H7 E. coli strain be recognized from other E. coli strains? A. Unlike other E. coli, it cannot ferment lactose. B. Unlike other E. coli, it cannot ferment mannose. C. Unlike other E. coli, it cannot ferment pyruvate. D. Unlike other E. coli, it cannot ferment sorbitol.* Difficulty: Difficult ASM Standard: 34 True/False 35. Glycolysis cannot occur in an anaerobic environment. Answer: False Difficulty: Easy Page 7 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism ASM Standard: 20, 22 36. Nitrogen is fixed to ammonia by cyanobacteria and other microbes. Answer: True Difficulty: Easy ASM Standard: 11, 20, 22, 23, 24 37. The light reactions of photosynthesis include an electron transport chain. Answer: True Difficulty: Moderate ASM Standard: N/A 38. Fermentation is necessary because it provides additional energy compared with glycolysis alone. Answer: False Difficulty: Moderate ASM Standard: N/A 39. E. coli can be distinguished from some if its close gram-negative relatives because it can ferment lactose. Answer: True Difficulty: Moderate ASM Standard: 11, 34 40. Oxygen is necessary for an electron transport chain to function. Answer: False Difficulty: Moderate ASM Standard: N/A 41. Mycobacterium tuberculosis can degrade cholesterol, making it more virulent. Answer: True Difficulty: Difficult ASM Standard: 11, 23 42. Cyclic photophosphorylation produces only ATP, but noncyclic photophosphorylation produces ATP and NADH. Answer: True Difficulty: Difficult ASM Standard: N/A Page 8 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Matching 43. Match each description with the best definition. A. chemoautotroph i. uses light energy and an inorganic carbon source B. chemoheterotroph ii. uses chemical energy and an inorganic carbon source C. photoautotroph iii. uses light energy and an organic carbon source D. photoheterotroph iv. uses chemical energy and an organic carbon source Answers: A. ii., B. iv., C. i., D. iii. Difficulty: Easy ASM Standard: 11, 20, 22 44. Match each term with its best example. A. chemoautotroph i. animals B. chemoheterotroph ii. iron-oxidizing bacteria C. photoautotroph iii. purple sulfur bacteria D. photoheterotroph iv. green nonsulfur bacteria Answers: A. ii., B. i., C. iii., D. iv. Difficulty: Moderate ASM Standard: 11, 20, 22 45. Match each word with the best definition. A. apoenzyme i. an inorganic enzyme helper molecule B. coenzyme ii. an active enzyme with its coenzyme or cofactor C. cofactor iii. an inactive enzyme lacking its coenzyme or cofactor D. holoenzyme iv. an organic enzyme helper molecule Answers: A. iii., B. iv., C. i., D. ii. Difficulty: Moderate ASM Standard: N/A 46. Match each reaction with the place that it occurs in eukaryotic cells. A. electron transport chain of cellular respiration i. stroma of chloroplast B. glycolysis ii. cytoplasm C. Krebs cycle iii. thylakoid membrane D. light-independent reactions (Calvin cycle) iv. inner mitochondrial membrane E. light reactions of photosynthesis v. mitochondrial matrix Answers: A. iv., B. ii., C. v., D. i., E. iii. Difficulty: Moderate ASM Standard: 11, 20, 22 47. Match each process with the best definition. A. aerobic respiration i. uses an electron transport chain with an inorganic molecule such as SO4 2– as the terminal electron acceptor Page 9 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism B. anaerobic respiration ii. regenerates NAD+ for glycolysis by donating an electron to an endogenous organic molecule, often pyruvate C. fermentation iii. uses an electron transport chain with O2 as the terminal electron acceptor Answers: A. iii., B. i., C. ii. Difficulty: Moderate ASM Standard: 11, 20, 22 48. Match each type of fermentation with some of its end products. A. alcohol i. acetic acid and other products B. butanediol ii. succinic acid and other products C. mixed acid iii. formic acid, lactic acid, and other products D. propionic acid iv. ethanol and CO2 only Answers: A. iv., B. iii., C. ii., D. i. Difficulty: Moderate ASM Standard: 11, 20, 22 49. Match each type of fermentation with a microbe that uses it. A. acetone-butanol-ethanol i. Candida, Saccharomyces B. alcohol ii. Escherichia, Shigella C. butanediol iii. Klebsiella, Enterobacter D. lactic acid iv. Clostridium acetobutylicum E. mixed acid v. Streptococcus, Lactobacillus Answers: A. iv., B. i., C. iii., D. v., E. ii. Difficulty: Difficult ASM Standard: 11 Fill in the Blank 50. Another name for the Embden-Meyerhof-Parnas pathway is ________. Answer: glycolysis Difficulty: Moderate ASM Standard: N/A 51. Cyclic photophosphorylation produces ________. Answer: ATP Difficulty: Easy ASM Standard: 23 52. In oxygenic photosynthesis, oxygen is released because ________is split to provide an electron to replace one that absorbs a photon of light. Page 10 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Answer: water Difficulty: Easy ASM Standard: N/A 53. The light-independent reactions of photosynthesis are also known as the ________. Answer: Calvin-Benson cycle (the names Calvin cycle or dark reactions may also be used, although the latter is not a preferred name) Difficulty: Moderate ASM Standard: N/A 54. Cyclic photophosphorylation uses only photosystem ________. Answer: I [PSI or P700] Difficulty: Moderate ASM Standard: N/A 55. The enzyme that brings CO2 into the light-independent reactions of photosynthesis, catalyzing the first reaction, is ________. Answer: ribulose bisphosphate carboxylate oxidase (RuBisCO) Difficulty: Moderate ASM Standard: N/A 56. ________ are bacteria and archaea that use methane as a carbon source. Answer: Methanotrophs Difficulty: Moderate ASM Standard: 11, 20, 22 57. Approximately 78% of the atmosphere is ________. Answer: nitrogen gas [N2] Difficulty: Easy ASM Standard: N/A 58. Rhizobia are bacteria that live in the root nodules of plants known as ________. Answer: legumes Difficulty: Moderate ASM Standard: 11, 20 59. The ________ is another name for the flow of electrons in noncyclic photophosphorylation. Answer: Z scheme Page 11 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Difficulty: Difficult ASM Standard: N/A 60. Acetate fermentation is used by ________. Answer: methanogens (students may also use acetogens, but that term is not in the chapter) Difficulty: Difficult ASM Standard: 11, 20, 22 Short Answer 61. Provide a basic overview of the major steps of the sulfur cycle. Sample Answer: Hydrogen sulfide is oxidized to elemental sulfur and then to sulfate. Difficulty: Easy ASM Standard: 24 62. What characteristics cause an organism to be classified as a chemoheterotroph? Sample Answer: Chemotrophs get their energy from chemical reactions. Heterotrophs obtain preformed organic molecules and cannot build organic molecules from inorganic molecules. Organisms that consume food (organic molecules) to get energy and organic molecules are chemoheterotrophs. Difficulty: Easy ASM Standard: N/A 63. What are xenobiotics? Sample Answer: Xenobiotics are chemicals produced by humans and released into the environment. Difficulty: Easy ASM Standard: N/A 64. In terms of water and electron donors, what is the difference between oxygenic and anoxygenic photosynthesis? Sample Answer: Oxygenic photosynthesis produces oxygen and anoxygenic photosynthesis does not. Oxygenic photosynthesis involves the use of water to donate an electron, releasing oxygen. In anoxygenic photosynthesis, other electron donors are used. Difficulty: Easy ASM Standard: 11, 20, 22 65. Describe an example of a microbe being used for bioremediation. Sample Answer: Rhodococcus and Pseudomonas are used to break down harmful compounds, such as those that could be released during an oil spill. Page 12 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Difficulty: Moderate ASM Standard: 11, 26, 23, 31 66. Compare the energy produced by fermentation with that produced by aerobic respiration. Sample Answer: Fermentation produces a net gain of two ATP molecules. In contrast, aerobic respiration produces a maximum of 38 ATP molecules. Difficulty: Moderate ASM Standard: 11, 20, 22 67. Compare the photosystems used in cyclic and noncyclic photophosphorylation, as well as the products of each. Sample Answer: Cyclic photophosphorylation uses photosystem I only (PSI or P700). It produces ATP. In contrast, noncyclic photophosphorylation uses photosystem I (PSI or P700) and photosystem II (PSII or P680). Noncyclic photophosphorylation produces ATP and NADPH. Difficulty: Moderate ASM Standard: 11 68. What is produced by the light-independent reactions (the Calvin cycle) of photosynthesis? Sample Answer: The light-independent reactions of photosynthesis produce glyceraldehyde3-phosphate. These reactions consume ATP and NADPH, producing ADP, Pi, and NADP+ that can be used for the light reactions. (Note that the last sentence is not explained clearly in the text, although the text mentions that ATP and NADPH are used.) Difficulty: Moderate ASM Standard: N/A 69. During glycolysis, how many ATP molecules are consumed and how many are produced? Sample Answer: During glycolysis, two ATP molecules are consumed and four ATP molecules are produced. There is a net gain of two ATP molecules. Difficulty: Easy ASM Standard: 11 70. What are the electron carrier molecules that deliver electrons to the electron transport chain in aerobic respiration? Sample Answer: In aerobic respiration, electrons are provided by NADH and FADH2. Difficulty: Easy ASM Standard: 11 71. What electron carrier in the electron transport chain can be used to distinguish similar bacterial species? Page 13 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Sample Answer: Cytochrome oxidase, the electron carrier that donates electrons to oxygen, differs among species and can be used in identification. Difficulty: Moderate ASM Standard: 11, 34 72. Where does the transition reaction occur in prokaryotic cells, compared with eukaryotic cells? Sample Answer: Prokaryotic cells do not have mitochondria, so the transition reaction takes place in the cytoplasm. In contrast, in eukaryotic cells, the transition reaction takes place in the mitochondrial matrix. Difficulty: Moderate ASM Standard: 9, 11, 20, 22 73. In prokaryotic cells, where does the electron transport chain of aerobic respiration take place? Sample Answer: In prokaryotic cells, the electron transport chain takes place on the cell membrane because these cells do not have mitochondria. Difficulty: Moderate ASM Standard: 9, 11, 22 74. The figure shows a chemical reaction. Explain whether the reaction is endergonic or exergonic. Sample Answer: The reaction is endergonic. The amount of energy in the products is higher than the amount of energy in the reactants, meaning that energy was absorbed from the environment during the reaction. You can tell that the amount of energy is higher in the products because the line is higher on the y-axis of the graph for the products. Difficulty: Difficult ASM Standard: N/A 75. Based on what you know about different metabolic types of microbes, what would be the carbon, energy, and electron requirements for a chemoorganoautotroph? Sample Answer: A chemoorganoautotroph would be an organism that used chemical reactions of organic molecules to gain energy and electrons but is also capable of fixing inorganic molecules to produce organic molecules. Page 14 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism Difficulty: Difficult ASM Standard: 20, 22 76. Explain redox potential and why it is important in understanding the electron transport chain. Sample Answer: Redox potential describes how easily a molecule acquires electrons. A molecule with a more positive redox potential will more readily accept an electron from another molecule, being reduced in the process. In the electron transport chain, an electron is passed from one acceptor to another, with each having a more positive redox potential than the last. Difficulty: Difficult ASM Standard: N/A Brief Essay Essay Question Rubric RATING Failing Below Average Competent Advanced Criteria for evaluati on Answer does not provide an argument. Answer contains inaccuracies. Writing is poor and contains numerous grammatical mistakes and misspellings. Answer fails to provide examples to support an argument. Writing is poor and grammatical errors are common. Answer is somewhat incoherent. Answer provides an argument with one or two examples that support it. Writing is acceptable for the college level but may contain one or two grammatical mistakes or misspellings. Answer clearly provides an argument with two or more excellent examples that support it; student makes the argument clearly and eloquently. Answer is well organized and free of grammatical errors and misspellings. POINT VALUE 0 1 2 3 Assume rating/grading scale for the question ranges from 0 to 3 points. 77. Compare the Embden-Meyerhof-Parnas, Entner-Doudoroff, and pentose phosphate pathways for breaking down glucose. Sample Answer: Student answers will vary but should include components of the following. The Embden-Meyerhof-Parnas pathway (EMP), or glycolysis, is the most common pathway and is found in most cells. The Entner-Doudoroff pathway (ED) can coexist with the EMP pathway in some cells. Other organisms use only the ED pathway. The pentose phosphate Page 15 of 16 OpenStax Microbiology Test Bank Chapter 8: Microbial Metabolism pathway occurs in all cells and is useful in biosynthesis. It is especially important when molecules with an odd number of carbons, proteins, and nucleic acids are needed. Difficulty: Moderate ASM Standard: 11 78. Explain the difference between substrate level phosphorylation and oxidative phosphorylation. Sample Answer: Student answers will vary but should include the following. Substrate level phosphorylation occurs when two reactions are coupled, one that releases energy and one that uses that energy to form ATP. Oxidative phosphorylation occurs when an electron transport chain is used to perform multiple oxidation reactions, providing the energy to produce ATP. Difficulty: Moderate ASM Standard: N/A 79. Explain at least three reasons why some cells may not use aerobic respiration even though it produces more energy than other forms of respiration. Sample Answer: Student answers will vary but should include the following. One possible reason is that a cell lacks an appropriate cytochrome oxidase to use in an electron transport chain. Cytochrome oxidase is needed to transfer electrons to oxygen. Another possible reason is that the cell may not have mechanisms to protect itself from damage caused by the presence of oxygen. When oxygen is present, reactive oxygen species, such as hydrogen peroxide and the superoxide radical, are present and can damage cells if the cells do not have mechanisms to protect themselves. Finally, the cell may be in an environment in which there is not enough oxygen for it to perform cellular respiration. Difficulty: Difficult ASM Standard: 11, 20, 22 80. Describe some ways that differences in metabolic abilities can be used to identify microbes. Sample Answer: Student answers will vary but should include components of the following. There are many ways that differences in metabolic abilities can be used to identify microbes. Multiple examples are included in the chapter. For example, an oxidase test can be used to distinguish Pseudomonas aeruginosa and Vibrio cholerae from negative Enterobacteriaceae because they use different cytochrome oxidases. The ability to ferment lactose distinguishes Escherichia coli from some other gram-negative bacteria. Additionally, O157:H7 E. coli can be distinguished from other E. coli strains because it cannot ferment sorbitol. Staphylococcus aureus can be distinguished from other staphylococci because it can ferment mannitol. Difficulty: Difficult ASM Standard: 22, 33, 34 This file is copyright 2017, Rice University. All rights reserved. Page 16 of 16