Ch. 5 Microbiology Test Microbial Metabolism

5) The use of enzymes is necessary to increase the activation energy requirements of a chemical reaction.

False

9) Both respiration and photosynthesis use water molecules for the donation of hydrogen ions.

False

24) Which of the following uses glucose for carbon and energy? A) chemoautotroph B) chemoheterotroph C) photoautotroph D) photoheterotroph

B

2) The pentose phosphate pathway can be characterized as an anabolic pathway.

False

3) In general, ATP is generated in catabolic pathways and expended in anabolic pathways.

False

14) A strictly fermentative bacterium produces energy A) by glycolysis only. B) by aerobic respiration only. C) by fermentation or aerobic respiration. D) only in the absence of oxygen. E) only in the presence of oxygen.

A

23) Which of the following uses CO2 for carbon and H2 for energy? A) chemoautotroph B) chemoheterotroph C) photoautotroph D) photoheterotroph

A

27) 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. A) 2, 4, 5 B) 1, 3, 4 C) 2, 3, 5 D) 1, 2, 3 E) All of the statements are true.

A

39) Gallionella bacteria can get energy from the reaction Fe2+ → Fe3+. This reaction is an example of A) oxidation. B) reduction. C) fermentation. D) photophosphorylation. E) the Calvin-Benson cycle.

A

44) What is the most acidic place in Figure 5.8? A) a B) b C) c D) d E) e

A

9) Fatty acids are oxidized in A) the Krebs cycle. B) the electron transport chain. C) glycolysis. D) the pentose phosphate pathway. E) the Entner-Doudoroff pathway.

A

11) Which of the following is the best definition of oxidative phosphorylation? A) Electrons are passed through a series of carriers to O2. B) A proton gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels, releasing energy that is used to generate ATP. C) ATP is directly transferred from a substrate to ADP. D) Electrons are passed through a series of carriers to an organic compound.

B

17) In noncyclic photophosphorylation, O2 is released from A) CO2. B) H2O. C) C6H12O6. D) sunlight. E) chlorophyll.

B

18) Which of the following is the best definition of fermentation? A) the partial reduction of glucose to pyruvic acid B) the partial oxidation of glucose with organic molecules serving as electron acceptors C) the complete catabolism of glucose to CO2 and H2O D) the production of energy by oxidative-level phosphorylation E) the production of energy by both substrate and oxidative phosphorylation

B

22) Assume you are growing bacteria on a lipid medium that started at pH 7. The action of bacterial lipases should cause the pH of the medium to A) increase. B) decrease. C) stay the same.

B

3) Which organism is NOT correctly matched to its energy source? A) photoheterotroph - light B) photoautotroph - CO2 C) chemoautotroph - Fe2+ D) chemoheterotroph - glucose E) chemoautotroph-NH3

B

30) Which of the following is TRUE about this reaction? NO3-+ 2H+ NO2- + H2O Nitrate ion Nitrite ion A) This process requires O2. B) This process occurs anaerobically. C) This process requires the electron transport system. D) This process requires light. E) This process requires O2 and the electron transport system.

B

32) 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? A) The maltose is toxic. B) O2 is in the medium. C) Not enough protein is provided. D) The temperature is too low. E) The temperature is too high.

B

34) An enzyme, citrate synthase, in the Krebs cycle is inhibited by ATP. This is an example of all of the following EXCEPT A) allosteric inhibition. B) competitive inhibition. C) feedback inhibition. D) noncompetitive inhibition.

B

37) 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? A) a B) b C) c D) d

B

43) In Figure 5.8, the path labeled "2" is the flow of A) electrons. B) protons. C) energy. D) water. E) glucose.

B

45) A urease test is used to identify Myobacterium tuberculosis because A) urease is a sign of tuberculosis. B) M. tuberculosis produces urease. C) urea accumulates during tuberculosis. D) some bacteria reduce nitrate ion. E) M. bovis can cause tuberculosis.

B

5) What type of reaction is in Figure 5.2? A) decarboxylation B) transamination C) dehydrogenation D) oxidation E) reduction

B

7) How would a noncompetitive inhibitor interfere with a reaction involving the enzyme shown in Figure 5.3? 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.

B

1) Which of the following compounds is NOT an enzyme? A) dehydrogenase B) cellulase C) coenzyme A D) β-galactosidase E) sucrase

C

10) Which of the graphs in Figure 5.5 best illustrates the activity of an enzyme that is saturated with substrate? A) a B) b C) c D) d E) e

C

15) The advantage of the pentose phosphate pathway is that it produces all of the following EXCEPT A) precursors for nucleic acids. B) precursors for the synthesis of glucose. C) three ATPs. D) NADPH. E) precursors for the synthesis of amino acids.

C

2) Which compound is being reduced in the reaction shown in Figure 5.1? A) isocitric acid and α-ketoglutaric acid B) α-ketoglutaric acid and NAD+ C) NAD+ D) NADH E) NADH and isocitric acid

C

26) Cyanobacteria are a type of A) chemoautotroph. B) chemoheterotroph. C) photoautotroph. D) photoheterotroph.

C

28) Microorganisms that catabolize sugars into ethanol and hydrogen gas would most likely be categorized as A) aerobic respirers. B) anaerobic respirers. C) heterolactic fermenters. D) homolactic fermenters. E) alcohol fermenters.

C

33) 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 A) these bacteria don't use O2. B) these bacteria get more energy anaerobically. C) aerobic metabolism is more efficient than fermentation. D) these bacteria cannot grow anaerobically.

C

35) If a cell is starved for ATP, which of the following pathways would most likely be shut down? A) Kreb's cycle B) glycolysis C) pentose phosphate pathway D) Krebs cycle and glycolysis

C

38) A bacterial culture grown in a glucose-peptide medium causes the pH to increase. The bacteria are most likely A) fermenting the glucose. B) oxidizing the glucose. C) using the peptides. D) not growing.

C

4) Which of the following statements about anaerobic respiration is FALSE? A) It yields lower amounts of ATP when compared to aerobic respiration. B) The complete Kreb's cycle is utilized. C) It involves the reduction of an organic final electron acceptor. D) It generates ATP. E) It requires cytochromes.

C

42) In Figure 5.8, the structure labeled "1" is A) NAD+. B) ATP synthase. C) a plasma membrane. D) a cell wall. E) cytoplasm.

C

12) Which of the following statements about substrate-level phosphorylation is FALSE? A) It involves the direct transfer of a high-energy phosphate group from an intermediate metabolic compound to ADP. B) No final electron acceptor is required. C) It occurs in glycolysis. D) The oxidation of intermediate metabolic compounds releases energy that is used to generate ATP. E) It occurs in the Krebs cycle.

D

13) Which of the following statements about photophosphorylation is FALSE? A) Light liberates an electron from chlorophyll. B) The oxidation of carrier molecules releases energy. C) Energy from oxidation reactions is used to generate ATP from ADP. D) It requires CO2. E) It occurs in photosynthesizing cells

D

16) Which of the following statements about beta oxidation is FALSE? A) It is a method of catabolizing fatty acids. B) It involves the formation of 2-carbon units. C) It involves the formation of acetyl-CoA. D) It is a step in glycolysis. E) It is used in petroleum degradation.

D

19) Which of the following is NOT necessary for respiration? A) cytochromes B) flavoproteins C) a source of electrons D) oxygen E) quinones

D

20) Which one of the following would you predict is an allosteric inhibitor of the Krebs cycle enzyme, α-ketoglutarate dehydrogenase? A) citric acid B) α-ketoglutaric acid C) NAD+ D) NADH E) ADP

D

21) In green and purple bacteria, electrons to reduce CO2 can come from A) CO2. B) H2O. C) C6H12O6. D) H2S. E) chlorophyll.

D

25) Which of the following has bacteriochlorophylls and uses alcohols for carbon? A) chemoautotroph B) chemoheterotroph C) photoautotroph D) photoheterotroph

D

29) Which of the following statements regarding metabolism is FALSE? A) Heat may be released in both anabolic and catabolic reactions. B) ATP is formed in catabolic reactions. C) ADP is formed in anabolic reactions. D) Anabolic reactions are degradative.

D

31) Which of the following statements regarding the Entner-Doudoroff pathway is TRUE? A) It involves glycolysis. B) It involves the pentose phosphate pathway. C) NADH is generated. D) ATP is generated. E) NADH and ATP are generated.

D

36) Which of the following statements regarding the glycolysis pathway is FALSE? A) Two pyruvate molecules are generated. B) Four ATP molecules are generated via substrate-level phosphorylation. C) Two NADH molecules are generated. D) One molecule of ATP is expended. E) Two molecules of water are generated.

D

41) Refer to Figure 5.8. In aerobic respiration, where is water formed? A) a B) b C) c D) d E) e

D

40) In Figure 5.8, where is ATP produced? A) a B) b C) c D) d E) e

E

6) What is the fate of pyruvic acid in an organism that uses aerobic respiration? A) It is reduced to lactic acid. B) It reacts with oxaloacetate to form citrate. C) It is oxidized in the electron transport chain. D) It is catabolized in glycolysis. E) It is converted into acetyl CoA.

E

8) How is ATP generated in the reaction shown in Figure 5.4? A) glycolysis B) fermentation C) photophosphorylation D) oxidative phosphorylation E) substrate-level phosphorylation

E

1) Catabolic reactions are generally degradative and hydrolytic.

True

10) Once an enzyme has converted substrates into products, the active site reverts back to its original form.

True

4) An apoenzyme that loses its coenzyme subunit will be non-functional.

True

6) Glycolysis is utilized by cells in both respiration and fermentation.

True

7) Carbon fixation occurs during the light-independent phase of photosynthesis.

True

8) Both respiration and photosynthesis require the use of an electron transport chain.

True