Test Bank for Microbiology An Introduction 11th Edition by Tortora Chapter Exam Name _ MULTIPLE CHOICE Choose the one alternative that best completes the statement or answers the question 1) Which of the following compounds is NOT an enzyme? 1) A) coenzyme A B) cellulase C) ?-galactosidase D) sucrase E) dehydrogenase Answer: A Explanation: A) B) C) D) E) 2) Which of the following statements about photophosphorylation is FALSE? 2) A) Energy from oxidation reactions is used to generate ATP from ADP B) Light liberates an electron from chlorophyll C) It occurs in photosynthesizing cells D) The oxidation of carrier molecules releases energy E) It requires CO2 Answer: E Explanation: A) B) C) D) E) 3) Gallionella bacteria can get energy from the reaction Fe2+ Fe3+ This reaction is an example of 3) A) the Calvin-Benson cycle B) reduction C) fermentation D) oxidation E) photophosphorylation Answer: D Explanation: A) B) C) D) E) 4) A bacterial culture grown in a glucose-peptide medium causes the pH to increase The bacteria are most likely 4) A) oxidizing the glucose B) using the peptides C) fermenting the glucose D) not growing Answer: B Explanation: A) B) C) D) 5) Which of the following statements about substratelevel phosphorylation is FALSE? 5) A) It occurs in glycolysis B) It involves the direct transfer of a high-energy phosphate group from an intermediate metabolic compound to ADP C) The oxidation of intermediate metabolic compounds releases energy that is used to generate ATP D) No final electron acceptor is required E) It occurs in the Krebs cycle Answer: C Explanation: A) B) C) D) E) 6) Which organism is NOT correctly matched to its energy source? 6) A) chemoautotroph – Fe2+ B) chemoheterotroph – glucose C) chemoautotroph-NH3 D) photoheterotroph – light E) photoautotroph – CO2 Answer: E Explanation: A) B) C) D) E) 7) Which of the following is the best definition of oxidative phosphorylation? 7) A) A proton gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels, releasing energy that is used to generate ATP B) Electrons are passed through a series of carriers to O2 C) Electrons are passed through a series of carriers to an organic compound D) ATP is directly transferred from a substrate to ADP Answer: A Explanation: A) B) C) D) 8) Which of the following statements regarding the glycolysis pathway is FALSE? 8) A) Two NADH molecules are generated B) One molecule of ATP is expended C) Two molecules of water are generated D) Two pyruvate molecules are generated E) Four ATP molecules are generated via substrate-level phosphorylation Answer: B Explanation: A) B) C) D) E) Figure 5.6 9) The rates of O2 and glucose consumption by a bacterial culture are shown in Figure 5.6 Assume a bacterial culture was grown in a glucose medium without O2 Then O2 was added at the time marked X The data indicate that 9) A) these bacteria B) these bacteria cannot grow anaerobically C) aerobic metabolism is more efficient than fermentation D) these bacteria get more energy anaerobically Answer: C Explanation: A) B) C) D) 10) If a cell is starved for ATP, which of the following pathways would most likely be shut down? 10) A) glycolysis B) Kreb’s cycl pathway D) Krebs cycle and glycolysis Answer: C Explanation: A) B) C) D) Figure 5.7 11) The graph at the left in Figure 5.7 shows the reaction rate for an enzyme at its optimum temperature Which graph shows enzyme activity at a higher temperature? don 11) A) a B) b C) c D) d Answer: B Explanation: A) B) C) D) 12) Which of the following statements are true? 1-Electron carriers are located at ribosomes 2-ATP is a common intermediate between catabolic and anabolic pathways 3-ATP is used for the long-term storage of energy and so is often found in storage granules 4-Anaerobic organisms are capable of generating ATP via respiration 5-ATP can be generated by the flow of protons across protein channels 12) A) 1, 2, B) 1, 3, C) 2, 3, D) 2, 4, E) All of the statements are true Answer: D Explanation: A) B) C) D) E) 13) Fatty acids are oxidized in 13) A) the pentose phosphate pathway B) the electron transport chain C) the Entner-Doudoroff pathway D) the Krebs cycle E) glycolysis Answer: D Explanation: A) B) C) D) E) 14) Which of the following is the best definition of fermentation? 14) A) the partial oxidation of glucose with organic molecules serving as electron acceptors B) the complete catabolism of glucose to CO2 and H2O C) the partial reduction of glucose to pyruvic acid D) the production of energy by oxidative-level phosphorylation E) the production of energy by both substrate and oxidative phosphorylation Answer: A Explanation: A) B) C) D) E) 15) What is the fate of pyruvic acid in an organism that uses aerobic respiration? 15) A) It is reduced to lactic acid B) It is catabolized in glycolysis C) It reacts with oxaloacetate to form citrate D) It is converted into acetyl CoA E) It is oxidized in the electron transport chain Answer: D Explanation: A) B) C) D) E) 16) A urease test is used to identify Myobacterium tuberculosis because 16) A) M bovis can cause tuberculosis B) some bacteria reduce nitrate ion C) urea accumulates during tuberculosis D) M tuberculosis produces urease E) urease is a sign of tuberculosis Answer: D Explanation: A) B) C) D) E) 17) In green and purple bacteria, electrons to reduce CO2 can come from 17) A) H2O B) H2S C) C6H12O6 D) chlorophyll E) CO2 Answer: B Explanation: A) B) C) D) E) 18) Which of the following uses CO2 for carbon and H2 for energy? 18) A) chemoheterotroph B) chemoautotroph C) photoheterotroph D) photoautotroph Answer: B Explanation: A) B) C) D) 19) Which of the following is NOT necessary for respiration? 19) A) quinones B) flavoproteins C) oxygen D) cytochromes E) a source of electrons Answer: C Explanation: A) B) C) D) E) 20) Which of the following statements regarding the Entner-Doudoroff pathway is TRUE? 20) A) ATP is generated B) NADH is generated C) It involves the pentose phosphate pathway D) It involves glycolysis E) NADH and ATP are generated Answer: A Explanation: A) B) C) D) E) Figure 5.8 21) In Figure 5.8, the structure labeled “1” is 21) A membrane C) NAD+ D) ATP synthase E) cytoplasm Answer: B Explanation: A) B) C) D) E) 22) Cyanobacteria are a type of 22) A) photoheterotroph B) chemoautotroph C) chemoheterotroph D) photoautotroph Answer: D Explanation: A) B) C) D) 23) A strictly fermentative bacterium produces energy 23) A) by aerobic respiration only B) only in the absence of oxygen C) by glycolysis only D) only in the presence of oxygen E) by fermentation or aerobic respiration Answer: C Explanation: A) B) C) D) E) Figure 5.4 24) How is ATP generated in the reaction shown in Figure 5.4? 24) A) photophosphorylation B) oxidative phosphorylation C) substratelevel phosphorylation D) fermentation E) glycolysis Answer: C Explanation: A) B) C) D) E) 25) Which one of the following would you predict is an allosteric inhibitor of the Krebs cycle enzyme, ?-ketoglutarate dehydrogenase? 25) A) ?-ketoglutaric acid B) ADP C) NADH D) citric acid E) NAD+ Answer: C Explanation: A) B) C) D) E) 26) In noncyclic photophosphorylation, O2 is released from 26) A) H2O B) chlorophyll C) sunlight D) CO2 E) C6H12O6 Answer: A Explanation: A) B) C) D) E) 27) Which of the following uses glucose for carbon and energy? 27) A) chemoheterotroph B) photoheterotroph C) photoautotroph D) chemoautotroph Answer: A Explanation: A) B) C) D) Figure 5.3 28) How would a noncompetitive inhibitor interfere with a reaction involving the enzyme shown in Figure 5.3? 28) A) It would bind to a B) It would bind to b C) It would bind to c D) It would bind to d E) The answer cannot be determined based on the information provided Answer: B Explanation: A) B) C) D) E) Figure 5.1 29) Which compound is being reduced in the reaction shown in Figure 5.1? 29) A) NADH B) NAD+ C) ?-ketoglutaric acid and NAD+ D) isocitric acid and ?-ketoglutaric acid E) NADH and isocitric acid Answer: B Explanation: A) B) C) D) E) 10 Figure 5.8 30) Refer to Figure 5.8 In aerobic respiration, where is water formed? 30) A) a B) b C) c D) d E) e Answer: D Explanation: A) B) C) D) E) 11 Figure 5.2 31) What type of reaction is in Figure 5.2? 31) A) reduction B) transamination C) dehydrogenation D) decarboxylation E) oxidation Answer: B Explanation: A) B) C) D) E) 32) Which of the following statements about beta oxidation is FALSE? 32) A) It is a method of catabolizing fatty acids B) It is a step in glycolysis C) It is used in petroleum degradation D) It involves the formation of acetyl-CoA E) It involves the formation of 2-carbon units Answer: B Explanation: A) B) C) D) E) 12 Figure 5.8 33) What is the most acidic place in Figure 5.8? 33) A) a B) b C) c D) d E) e Answer: A Explanation: A) B) C) D) E) 34) Which of the following is TRUE about this reaction? NO3 -+ 2H+ Pseudomonas NO2 – + H2O Nitrate ion Nitrite ion 34) A) This process occurs anaerobically B) This process requires O2 C) This process requires the electron transport system D) This process requires light E) This process requires O2 and the electron transport system Answer: A Explanation: A) B) C) D) E) 13 35) Microorganisms that catabolize sugars into ethanol and hydrogen gas would most likely be categorized as 35) A) aerobic respirers B) homolactic fermenters C) alcohol fermenters D) anaerobic respirers E) heterolactic fermenters Answer: E Explanation: A) B) C) D) E) Figure 5.8 36) In Figure 5.8, the path labeled “2” is the flow o C) protons D) energy E) electrons Answer: C Explanation: A) B) C) D) E) 37) Which of the following statements regarding metabolism is FALSE? 37) A) Heat may be released in both anabolic and catabolic reactions B) ADP is formed in anabolic reactions C) ATP is formed in catabolic reactions D) Anabolic reactions are degradative Answer: D Explanation: A) B) C) D) 14 38) The advantage of the pentose phosphate pathway is that it produces all of the following EXCEPT 38) A) precursors for the synthesis of glucose B) NADPH C) three ATPs D) precursors for the synthesis of amino acids E) precursors for nucleic acids Answer: C Explanation: A) B) C) D) E) 39) Which of the following has bacteriochlorophylls and uses alcohols for carbon? 39) A) chemoautotroph B) photoautotroph C) photoheterotroph D) chemoheterotroph Answer: C Explanation: A) B) C) D) 40) Assume you are growing bacteria on a lipid medium that started at pH The action of bacterial lipases should cause the pH of the medium to 40) A) stay the same B) decrease C) increase Answer: B Explanation: A) B) C) 15 Figure 5.8 41) In Figure 5.8, where is ATP produced? 41) A) a B) b C) c D) d E) e Answer: E Explanation: A) B) C) D) E) 42) An enzyme, citrate synthase, in the Krebs cycle is inhibited by ATP This is an example of all of the following EXCEPT 42) A) feedback inhibition B) competitive inhibition C) noncompetitive inhibition D) allosteric inhibition Answer: B Explanation: A) B) C) D) 16 Figure 5.5 43) Which of the graphs in Figure 5.5 best illustrates the activity of an enzyme that is saturated with substrate? 43) A) a B) b C) c D) d E) e Answer: C Explanation: A) B) C) D) E) 44) Assume you are working for a chemical company and are responsible for growing a yeast culture that produces ethanol The yeasts are growing well on the maltose medium but are not producing alcohol What is the most likely explanation? 44) A) The maltose is toxic B) O2 is in the medium C) The temperature is too low D) The temperature is too high E) Not enough protein is provided Answer: B Explanation: A) B) C) D) E) 45) Which of the following statements about anaerobic respiration is FALSE? 45) A) The complete B) It yields lower amounts of ATP when compared to aerobic respiration C) It involves the reduction of an organic final electron acceptor D) It generates ATP E) It requires cytochromes Answer: C Explanation: A) B) C) D) E) 17 TRUE/FALSE Write ‘T’ if the statement is true and ‘F 46) An apoenzyme that loses its coenzyme subunit will be non-functional 46) Answer: True False Explanation: 47) Glycolysis is utilized by cells in both respiration and fermentation 47) Answer: True False Explanation: 48) The pentose phosphate pathway can be characterized as an anabolic pathway 48) Answer: True False Explanation: 49) Both respiration and photosynthesis require the use of an electron transport chain 49) Answer: True False Explanation: 50) Both respiration and photosynthesis use water molecules for the donation of hydrogen ions 50) Answer: True False Explanation: 51) Catabolic reactions are generally degradative and hydrolytic 51) Answer: True False Explanation: 52) Once an enzyme has converted substrates into products, the active site reverts back to its original form 52) Answer: True False Explanation: 53) The use of enzymes is necessary to increase the activation energy requirements of a chemical reaction 53) Answer: True False Explanation: 54) Carbon fixation occurs during the light-independent phase of photosynthesis 54) Answer: True False Explanation: 55) In general, ATP is generated in catabolic pathways and expended in anabolic pathways 55) Answer: True False Explanation: ESSAY Write your answer in the space provided or on a separate sheet of paper 56) Rhodopseudomonas is an anaerobic photoautotroph that uses organic compounds as an electron donor It is also capable of chemoheterotrophic metabolism Diagram the metabolic pathways of this bacterium Answer: 18 57) Streptococcus lacks an electron transport chain How does this bacterium K reoxidize NADH? Where is the NADH formed? Answer: 58) Differentiate the following two laboratory tests: starch hydrolysis and starch fermentation Answer: 59) You look in the refrigerator and find some orange drink you had forgotten was there The drink now has an “off” taste and bubbles Whatexplanationisthefor themostchangeslikelyin the drink? Answer: 60) Compare and contrast photophosphorylation and oxidative phosphorylation Answer: 19 Answer Key Testname: C5 1) A 2) E 3) D 4) B 5) C 6) E 7) A 8) B 9) C 10) C 11) B 12) D 13) D 14) A 15) D 16) D 17) B 18) B 19) C 20) A 21) B 22) D 23) C 24) C 25) C 26) A 27) A 28) B 29) B 30) D 31) B 32) B 33) A 34) A 35) E 36) C 37) D 38) C 39) C 40) B 41) E 42) B 43) C 44) B 45) C 46) TRUE 47) TRUE 48) FALSE 49) TRUE 50) FALSE