Microbial Metabolism - Answer Key

Brock Biology of Microorganisms, Microbial Metabolism Multiple Choice Questions 1) The sum of all biosynthetic reactions in a cell is known as A) metabolism. B) anabolism. C) catabolism. D) synthatabolism. Answer: B Bloom's Taxonomy: Knowledge Chapter Section: 3.13 2) Based on the functional roles of phosphate in various microbial metabolisms, deduce which compounds phosphate exists as in microorganisms. A) organic compounds B) inorganic compounds C) both organic and inorganic compounds D) neither organic nor inorganic compounds Answer: C Bloom's Taxonomy: Evaluation Chapter Section: 3.1 3) Which of the following would be used by a chemoorganotroph for energy? A) C2H3O2B) H2 C) CO2 D) H+ Answer: A Bloom's Taxonomy: Comprehension Chapter Section: 3.3 4) Which of the following statements is FALSE? A) Most bacteria are capable of using ammonia as their sole nitrogen source. B) Some bacteria are able to use nitrates or nitrogen gas as their nitrogen source. C) Most available nitrogen is in organic forms. D) Nitrogen is a major component of proteins and nucleic acids. Answer: C Bloom's Taxonomy: Knowledge Chapter Section: 3.1 5) All microorganisms require A) carbon, iron, and sodium. B) phosphorus, aluminum, and sodium. C) calcium, potassium, and magnesium. D) phosphorus, selenium, and sulfur. Answer: D Bloom's Taxonomy: Knowledge Chapter Section: 3.1 6) Which element functions BOTH as an enzyme cofactor and as a stabilizer of ribosomes and nucleic acids? A) iron B) hydrogen C) zinc D) magnesium Answer: D Bloom's Taxonomy: Knowledge Chapter Section: 3.1 7) Based on your understanding of metabolism, generalize when an enzyme's rate of activity can be changed. A) before enzyme production B) during enzyme production C) after enzyme production D) at any point–before, during, or after enzyme production Answer: C Bloom's Taxonomy: Synthesis Chapter Section: 3.5 8) The change in Gibbs free energy for a particular reaction is MOST useful in determining A) the amount of energy catalysts required for biosynthesis or catabolism. B) the potential metabolic reaction rate. C) whether there will be a requirement or production of energy. D) energy stored in each compound. Answer: C Bloom's Taxonomy: Application Chapter Section: 3.4 9) Which is an example of a micronutrient? A) arginine B) inorganic phosphorous C) iron D) vitamin B12 Answer: C Bloom's Taxonomy: Comprehension Chapter Section: 3.1 10) Aseptic technique refers to A) the microbial inoculum placed into a test tube or onto a Petri plate. B) a series of practices to avoid contamination. C) the autoclave and other sterilizing procedures. D) cleanliness in the laboratory. Answer: B Bloom's Taxonomy: Knowledge Chapter Section: 3.2 11) To ensure growth of a newly discovered bacterium with unknown nutritional requirements, it would be best to begin with a ________ medium rather than a ________ medium. A) complex / minimal B) minimal / complex C) selective / complex D) selective / differential Answer: A Bloom's Taxonomy: Evaluation Chapter Section: 3.2 12) If ΔG0' is negative, the reaction is A) exergonic and requires the input of energy. B) endergonic and requires the input of energy. C) exergonic and energy will be released. D) endergonic and energy will be released. Answer: C Bloom's Taxonomy: Knowledge Chapter Section: 3.4 13) Activation energy is the energy A) required to transform all reactants into their reactive state. B) given off as the products in a chemical reaction are formed. C) absorbed as ΔG0' moves from negative to positive. D) needed by an enzyme to catalyze a reaction without coenzymes. Answer: A Bloom's Taxonomy: Knowledge Chapter Section: 3.5 14) A catalyst A) requires more reactants but makes the reaction rate faster. B) increases the amount of reactants produced but does not change the rate. C) changes the rate of the reaction but does not change the end amount of products. D) changes both the rate of a reaction and the amount of the product that will be obtained as the reaction is completed. Answer: C Bloom's Taxonomy: Comprehension Chapter Section: 3.5 15) The portion of an enzyme to which substrates bind is referred to as the A) substrate complex. B) active site. C) catalytic site. D) junction of van der Waals forces. Answer: B Bloom's Taxonomy: Knowledge Chapter Section: 3.5 16) What is the difference between a coenzyme and a prosthetic group? A) Coenzymes are essential for an enzyme's function and prosthetic groups only enhance its reaction rate. B) Coenzymes are weakly bound whereas prosthetic groups are strongly bound to their respective enzymes. C) Coenzymes are organic cofactors and prosthetic groups are inorganic cofactors. D) Coenzymes require additional ions to bind to enzymes but prosthetic groups are able to directly interact with enzymes. Answer: B Bloom's Taxonomy: Analysis Chapter Section: 3.5 17) If an oxidation reaction occurs A) simultaneous reduction of a different compound will also occur, because electrons do not generally exist alone in solution. B) another oxidation reaction will occur for a complete reaction, because one oxidation event is considered a half reaction. C) a cell is undergoing aerobic respiration, because oxygen is being used. D) a reduction reaction would not occur, because they are opposite reaction mechanisms. Answer: A Bloom's Taxonomy: Knowledge Chapter Section: 3.6 18) The class of macromolecules in microorganisms that contributes MOST to biomass is A) carbohydrates. B) DNA. C) lipids. D) proteins. Answer: D Bloom's Taxonomy: Knowledge Chapter Section: 3.1 19) A chemoorganotroph and a chemolithotroph in the same environment would NOT compete for A) oxygen. B) carbon. C) nitrogen. D) phosphorous. Answer: B Bloom's Taxonomy: Analysis Chapter Section: 3.3 20) A chemoorganotroph and a photoautotroph in the same environment would NOT compete for A) oxygen. B) carbon. C) nitrogen. D) carbon and oxygen. Answer: D Bloom's Taxonomy: Analysis Chapter Section: 3.3 21) The Embden-Meyerhof-Parnas pathway is another name for A) the citric acid cycle. B) glycolysis. C) electron transport. D) NADH production. Answer: B Bloom's Taxonomy: Knowledge Chapter Section: 3.8 22) The net gain of ATP per molecule of glucose fermented is A) 1. B) 2. C) 4. D) 8. Answer: B Bloom's Taxonomy: Knowledge Chapter Section: 3.8 23) Which of the following is a common energy storage polymer in microorganisms? A) acetyl~S-CoA B) glycogen C) adenosine triphosphate D) H2 Answer: B Bloom's Taxonomy: Knowledge Chapter Section: 3.8 24) Fermentation has a relatively low ATP yield compared to aerobic respiration because A) more reducing equivalents are used for anaerobic catabolism. B) less ATP is consumed during the first stage of aerobic catabolism. C) oxidative phosphorylation yields a lot of ATP. D) substrate-level phosphorylation yields a lot of ATP. Answer: C Bloom's Taxonomy: Comprehension Chapter Section: 3.8 25) From the standpoint of the microorganism, in glycolysis the crucial product is A) ATP; the fermentation products are waste products. B) ethanol or lactate; ATP is a waste product. C) CO2; ATP is a waste product. D) not relevant because glycolysis is not a major pathway. Answer: A Bloom's Taxonomy: Comprehension Chapter Section: 3.8 26) In aerobic respiration, the final electron acceptor is A) hydrogen. B) oxygen. C) water. D) ATP. Answer: B Bloom's Taxonomy: Comprehension Chapter Section: 3.10 27) Which of the following is NOT membrane-associated? A) NADH dehydrogenases B) flavoproteins C) cytochromes D) Cytochromes, flavoproteins, and NADH dehydrogenases all can be membrane-associated. Answer: D Bloom's Taxonomy: Knowledge Chapter Section: 3.10 28) During electron transport reactions, A) OH- accumulates on the outside of the membrane while H+ accumulates on the inside. B) OH- accumulates on the inside of the membrane while H+ accumulates on the outside. C) both OH- and H+ accumulate on the inside of the membrane. D) both OH- and H+ accumulate on the outside of the membrane. Answer: B Bloom's Taxonomy: Knowledge Chapter Section: 3.11 29) The rising of bread dough is the result of A) biotin production. B) carbon dioxide produced by fermentation. C) oxidative phosphorylation. D) oxygen being released. Answer: B Bloom's Taxonomy: Analysis Chapter Section: 3.11 30) Which intermediate compound(s) in the citric acid cycle is/are often used for biosynthetic pathways as well as carbon catabolism? A) α-ketoglutarate B) oxaloacetate C) succinyl-CoA D) α-ketoglutarate, oxaloacetate, and succinyl-CoA Answer: D Bloom's Taxonomy: Knowledge Chapter Section: 3.12 31) Microbial growth on the two-carbon acetate substrate invokes A) the citric acid cycle for aerobic catabolism. B) both the citric acid and glyoxylate pathways. C) the glyoxylate pathway. D) the glyoxylate and glycolysis pathways. Answer: B Bloom's Taxonomy: Knowledge Chapter Section: 3.12 32) Which feature of anaerobic and aerobic respiration is different between the two catabolic strategies? A) electron donor B) electron acceptor C) use of electron transport D) use of proton motive force Answer: B Bloom's Taxonomy: Analysis Chapter Section: 3.13 33) For a carbon source, chemoorganotrophs generally use compounds such as A) acetate, succinate, and glucose. B) bicarbonate and carbon dioxide. C) nitrate and nitrite. D) acetate, bicarbonate, and nitrate. Answer: A Bloom's Taxonomy: Comprehension Chapter Section: 3.3 34) All of the following are non-protein electron carriers EXCEPT A) FADH2. B) FMNH2. C) cytochromes. D) quinones. Answer: C Bloom's Taxonomy: Comprehension Chapter Section: 3.10 35) Which two metabolic processes are MOST dissimilar? A) citric acid cycle and glycolysis B) glycolysis and gluconeogenesis C) proton motive force and substrate-level phosphorylation D) pentose phosphate pathway and glycolysis Answer: B Bloom's Taxonomy: Comprehension Chapter Section: 3.14 36) How does the proton motive force lead to production of ATP? A) ATPase requires one proton to make one ATP. B) Protons must be pumped against a concentration gradient from outside of the cell into the cell to rotate the F0 subunit of ATPase for the F1 subunit to make ATP. C) Oxidative phosphorylation of ADP by ATP synthase requires protons as cofactors in the reaction. D) Translocation of three to four protons drives the F0 component of ATPase which in turn phosphorylates one ADP into ATP. Answer: D Bloom's Taxonomy: Knowledge Chapter Section: 3.11 37) Five-carbon sugars are used in the A) biosynthesis of DNA and RNA. B) catabolic pentose phosphate pathway for carbon and energy. C) biosynthesis of DNA and RNA as well as catabolic pentose phosphate pathway. D) activation of pentoses to form glycogen for energy storage. Answer: A Bloom's Taxonomy: Knowledge Chapter Section: 3.14 38) Improperly functioning acyl carrier proteins (ACPs) would likely result in A) a physiological shift to anaerobic metabolism where an energized membrane is less important for energy production. B) enhanced growth of a bacterium due to faster growth substrate uptake by a weakened membrane. C) no harm to bacteria, because only archaeons and eukaryotes use ACPs for fatty acid biosynthesis. D) death for a bacterium due to poor lipid bilayer integrity. Answer: D Bloom's Taxonomy: Analysis Chapter Section: 3.16 39) A bacterium running low on NADPH could ________ to generate more of this coenzyme. A) degrade an amino acid or nucleic acid B) invoke the pentose phosphate pathway C) degrade a fatty acid D) use a broad specificity phosphatase with inorganic phosphatase and NADH Answer: B Bloom's Taxonomy: Application Chapter Section: 3.14 40) One example of an electron acceptor that can be used in anaerobic respiration is A) NADH. B) water. C) nitrate. D) FMN. Answer: C Bloom's Taxonomy: Application Chapter Section: 3.14 41) When culturing a chemoorganoheterophic bacterium, what outcome is LEAST likely to occur if ammonia and phosphate are provided at equal concentrations? A) Cells require much less P to grow than N, so extra P will be used for ATP synthesis and result in a faster growth rate. B) Cells will never consume all of the phosphate, because N is needed in higher quantities than P. C) The final biomass of cells will be no different than if only 50% of the phosphate was provided. D) The bacteria will import all of the ammonia to use for biosynthetic pathways. Answer: A Bloom's Taxonomy: Synthesis Chapter Section: 3.1 42) Most of the carbon in amino acid biosynthesis comes from A) citric acid cycle intermediates. B) citric acid cycle intermediates and glycolysis products. C) glycolysis products. D) glycolysis intermediates and products. Answer: B Bloom's Taxonomy: Knowledge Chapter Section: 3.15 43) Which metabolic cycle or pathway is LEAST likely to be invoked during the biosynthesis of DNA? A) citric acid cycle B) glycolysis C) gluconeogenesis D) pentose phosphate pathway Answer: C Bloom's Taxonomy: Evaluation Chapter Section: 3.15 44) Hypothetically, if electron pools existed in sufficient numbers for enzymes to use in metabolic reactions, A) a higher diversity of cytochromes would likely be observed. B) cytochromes would be unnecessary for cells and quinones would be more important. C) Q-cycle reactions would no longer be necessary for electron transport, but the proton motive force would otherwise be unchanged. D) most metabolic pathways for both anabolism and catabolism would have to be rewritten. Answer: D Bloom's Taxonomy: Synthesis Chapter Section: 3.11 45) Which metabolic strategy does NOT invoke the proton motive force for energy conservation? A) aerobic catabolism B) anaerobic C) chemoorganotrophy D) photoautrophy Answer: B Bloom's Taxonomy: Comprehension Chapter Section: 3.13 True/False Questions 1) A bacterial isolate that grows better on a nutrient agar plate supplemented with amino acids but still grows in a nutrient agar plate lacking amino acids suggests amino acids are trace nutrients for the isolate. Answer: FALSE Bloom's Taxonomy: Evaluation Chapter Section: 3.1 2) Regeneration of oxaloacetate is essential for the citric acid cycle to be cyclical. Answer: TRUE Bloom's Taxonomy: Knowledge Chapter Section: 3.12 3) Depending on the particular metabolism of a bacterium, electron transport can be used to energize and rotate ATP synthase. Answer: FALSE Bloom's Taxonomy: Comprehension Chapter Section: 3.11 4) Each amino acid made during protein biosynthesis first requires a separate biosynthetic pathway to be invoked by a cell. Answer: FALSE Bloom's Taxonomy: Knowledge Chapter Section: 3.15 5) The terminating step of moving electrons onto oxygen releases additional ATP during aerobic metabolism not made during anaerobic growth. Answer: FALSE Bloom's Taxonomy: Comprehension Chapter Section: 3.11 6) Nitrogenases not only reduce N2 but also can act on acetylene (C2H2). Answer: TRUE Bloom's Taxonomy: Knowledge Chapter Section: 3.17 7) Due to the number of phosphate groups, ATP has approximately three times more energy stored than AMP, and ADP has approximately two-thirds the energy stored of ATP. Answer: FALSE Bloom's Taxonomy: Knowledge Chapter Section: 3.7