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Test bank for Brock Biology of
Microorganisms, 16th Edition by
Michael T. Madigan
1. The metabolic diversity of photosynthetic bacteria stems from different
a. bacteriochlorophylls and pigments they contain.
b. light-harvesting complexes, electron donors, and
organic compounds they produce.
c. unrelated taxa capable of photosynthesis.
d. chlorophylls they can have and organic compounds they can produce.
ANSWER: b. light-harvesting complexes, electron donors, and organic compounds
they produce.
2. The process by which electrons from the quinone pool are forced against
the thermodynamic gradient to reduce NAD+ to NADH is called reverse
a. electron transport.
b. reduction
c. proton motive force.
d. energy flow.
ANSWER: a. electron transport.
3. In most cases, the final product of sulfur oxidation is
a. sulfate
b. elemental sulfur.
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c. thiosulfate
d. hydrogen sulfide.
ANSWER: a. sulfate
4. What metabolic advantage do cells have in storing the elemental sulfur
byproduct from sulfide oxidation?
a. The byproduct can be used for other biosynthetic pathways that use sulfur, such
as Rieske Fe-S proteins.
b. Sulfur decreases the intracellular acidification for non-acid-tolerant sulfide
oxidizers.
c. The cells avoid producing transport energy waste to secrete the sulfur.
d. The byproduct serves as an electron reserve for subsequent oxidation.
ANSWER: d. The byproduct serves as an electron reserve for subsequent
oxidation.
5. Which of the following are NOT found within the photosynthetic gene
cluster of Rhodobacter (a purple phototrophic bacterium)?
a. genes encoding reaction center and light-harvesting photocomplexes
b. genes encoding proteins involved in bacteriochlorophyll biosynthesis
c. genes encoding proteins involved in carotenoid biosynthesis
d. genes encoding proteins involved in phycobiliprotein biosynthesis
ANSWER: d. genes encoding proteins involved in phycobiliprotein biosynthesis
6. Glucose fermentation by Clostridium spp. produce ATP only when acetate
and butyrate are produced. Why do these organisms produce acetone and
butanol after strong initial activity of generating ATP with acetate and
butyrate byproducts?
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a. Acetate and butyrate are no longer needed for biosynthetic pathways.
b. Acetone and butanol serve as better sources for NAD(P)+ reduction.
c. Acetate and butyrate accumulation creates a deadly acidic environment, which
acetone and butanol do not.
d. Acetone and butanol production is favored for stability to store intracellular
carbon sources for potential nutrient poor conditions.
ANSWER: c. Acetate and butyrate accumulation creates a deadly acidic
environment, which acetone and butanol do not.
7. Which metabolic strategy's existence suggests rapid growth is NOT always
the best strategy to survive in the environment?
a. anaerobic fermentation
b. syntrophy
c. methylotrophy
d. disproportionation
ANSWER: b. syntrophy
8. A researcher lacked the necessary equipment to measure methane
production so instead monitored CO2 concentration as the unknown archaeon
grew and produced methane. Why might CO2 NOT decrease but methane
still increase?
a. CO2 is not a carbon source used by methanogens.
b. CO2 was used an electron donor but not as a carbon substrate.
c. Methanogenic Archaea containing carboxysomes likely made measuring small
losses of CO2 difficult to conclude.
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d. An alternative carbon source such as methanol was used.
ANSWER: d. An alternative carbon source such as methanol was used.
9. What products would be expected to form during anoxic degradation of the
seven-carbon compound benzoate following reduction and cleavage of the
aromatic ring?
a. 2 three-carbon compounds and CO2
b. 3 two-carbon compounds and CO2
c. 1 three-carbon compound and 1 four-carbon compound
d. 1 three-carbon compound and 2 two-carbon compounds
ANSWER: d. 1 three-carbon compound and 2 two-carbon compounds
10. In contrast to chlorophylls, carotenoids function
a. to convert reactive oxygen species into usable energy.
b. to quench toxic oxygen species.
c. as accessory pigments that enable absorption of energy from higher
wavelengths.
d. primarily as photoprotection (but they also transfer some absorbed energy into
reaction centers).
ANSWER: b. to quench toxic oxygen species.
11. Which of the following statements is FALSE?
a. Microbial cells exclude the cells of plants and animals.
b. Microbial cells include both bacteria and viruses.
c. Microbial cells carry out their life processes of growth independently.
Test bank for Brock Biology of
Microorganisms, 16th Edition by
Michael T. Madigan
1. The metabolic diversity of photosynthetic bacteria stems from different
a. bacteriochlorophylls and pigments they contain.
b. light-harvesting complexes, electron donors, and
organic compounds they produce.
c. unrelated taxa capable of photosynthesis.
d. chlorophylls they can have and organic compounds they can produce.
ANSWER: b. light-harvesting complexes, electron donors, and organic compounds
they produce.
2. The process by which electrons from the quinone pool are forced against
the thermodynamic gradient to reduce NAD+ to NADH is called reverse
a. electron transport.
b. reduction
c. proton motive force.
d. energy flow.
ANSWER: a. electron transport.
3. In most cases, the final product of sulfur oxidation is
a. sulfate
b. elemental sulfur.
,2|Page
c. thiosulfate
d. hydrogen sulfide.
ANSWER: a. sulfate
4. What metabolic advantage do cells have in storing the elemental sulfur
byproduct from sulfide oxidation?
a. The byproduct can be used for other biosynthetic pathways that use sulfur, such
as Rieske Fe-S proteins.
b. Sulfur decreases the intracellular acidification for non-acid-tolerant sulfide
oxidizers.
c. The cells avoid producing transport energy waste to secrete the sulfur.
d. The byproduct serves as an electron reserve for subsequent oxidation.
ANSWER: d. The byproduct serves as an electron reserve for subsequent
oxidation.
5. Which of the following are NOT found within the photosynthetic gene
cluster of Rhodobacter (a purple phototrophic bacterium)?
a. genes encoding reaction center and light-harvesting photocomplexes
b. genes encoding proteins involved in bacteriochlorophyll biosynthesis
c. genes encoding proteins involved in carotenoid biosynthesis
d. genes encoding proteins involved in phycobiliprotein biosynthesis
ANSWER: d. genes encoding proteins involved in phycobiliprotein biosynthesis
6. Glucose fermentation by Clostridium spp. produce ATP only when acetate
and butyrate are produced. Why do these organisms produce acetone and
butanol after strong initial activity of generating ATP with acetate and
butyrate byproducts?
,3|Page
a. Acetate and butyrate are no longer needed for biosynthetic pathways.
b. Acetone and butanol serve as better sources for NAD(P)+ reduction.
c. Acetate and butyrate accumulation creates a deadly acidic environment, which
acetone and butanol do not.
d. Acetone and butanol production is favored for stability to store intracellular
carbon sources for potential nutrient poor conditions.
ANSWER: c. Acetate and butyrate accumulation creates a deadly acidic
environment, which acetone and butanol do not.
7. Which metabolic strategy's existence suggests rapid growth is NOT always
the best strategy to survive in the environment?
a. anaerobic fermentation
b. syntrophy
c. methylotrophy
d. disproportionation
ANSWER: b. syntrophy
8. A researcher lacked the necessary equipment to measure methane
production so instead monitored CO2 concentration as the unknown archaeon
grew and produced methane. Why might CO2 NOT decrease but methane
still increase?
a. CO2 is not a carbon source used by methanogens.
b. CO2 was used an electron donor but not as a carbon substrate.
c. Methanogenic Archaea containing carboxysomes likely made measuring small
losses of CO2 difficult to conclude.
, 4|Page
d. An alternative carbon source such as methanol was used.
ANSWER: d. An alternative carbon source such as methanol was used.
9. What products would be expected to form during anoxic degradation of the
seven-carbon compound benzoate following reduction and cleavage of the
aromatic ring?
a. 2 three-carbon compounds and CO2
b. 3 two-carbon compounds and CO2
c. 1 three-carbon compound and 1 four-carbon compound
d. 1 three-carbon compound and 2 two-carbon compounds
ANSWER: d. 1 three-carbon compound and 2 two-carbon compounds
10. In contrast to chlorophylls, carotenoids function
a. to convert reactive oxygen species into usable energy.
b. to quench toxic oxygen species.
c. as accessory pigments that enable absorption of energy from higher
wavelengths.
d. primarily as photoprotection (but they also transfer some absorbed energy into
reaction centers).
ANSWER: b. to quench toxic oxygen species.
11. Which of the following statements is FALSE?
a. Microbial cells exclude the cells of plants and animals.
b. Microbial cells include both bacteria and viruses.
c. Microbial cells carry out their life processes of growth independently.
