Microbiology: An Introduction, 12e (Tortora)
Chapter 5 Microbial Metabolism
5.1 Multiple-Choice Questions
1) Which of the following compounds is NOT an enzyme?
A) dehydrogenase
B) cellulase
C) coenzyme A
D) β-galactosidase
E) sucrase
2) Figure 5.1
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
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
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. 5) Figure 5.2
What type of reaction is in Figure 5.2?
A) decarboxylation
B) transamination
C) dehydrogenation
D) oxidation
E) reduction
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.
7) Figure 5.3
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.
8) Figure 5.4 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
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.
10) Figure 5.5
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
11) Which of the following is the best definition of oxidative phosphorylation?
A) Electrons are passed through a series of carriers to O 2.
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.
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 to a lesser degree in the Krebs cycle than in glycolysis.
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.
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.
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.
16) Which biochemical process is NOT used during glycolysis?
A) substrate-level phosphorylation
B) oxidation-reduction
C) carbohydrate catabolism
D) beta oxidation
E) enzymatic reactions
17) In noncyclic photophosphorylation, O 2 is released from
A) CO2.
B) H2O.
C) C6H12O6.
D) sunlight.
E) chlorophyll.
Chapter 5 Microbial Metabolism
5.1 Multiple-Choice Questions
1) Which of the following compounds is NOT an enzyme?
A) dehydrogenase
B) cellulase
C) coenzyme A
D) β-galactosidase
E) sucrase
2) Figure 5.1
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
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
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. 5) Figure 5.2
What type of reaction is in Figure 5.2?
A) decarboxylation
B) transamination
C) dehydrogenation
D) oxidation
E) reduction
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.
7) Figure 5.3
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.
8) Figure 5.4 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
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.
10) Figure 5.5
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
11) Which of the following is the best definition of oxidative phosphorylation?
A) Electrons are passed through a series of carriers to O 2.
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.
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 to a lesser degree in the Krebs cycle than in glycolysis.
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.
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.
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.
16) Which biochemical process is NOT used during glycolysis?
A) substrate-level phosphorylation
B) oxidation-reduction
C) carbohydrate catabolism
D) beta oxidation
E) enzymatic reactions
17) In noncyclic photophosphorylation, O 2 is released from
A) CO2.
B) H2O.
C) C6H12O6.
D) sunlight.
E) chlorophyll.
