Download Brock Biology of Microorganisms, 11e (Madigan/Martinko)

Chapter 17: Metabolic Diversity
1) The absorption of __________ by chlorophyll begins the process of __________.
A) ATP / photosynthetic energy conversion
B) light quanta / autotrophy
C) ATP / autotrophy
D) light quanta / photosynthetic energy conversion
Answer: D
2) Whether an organism is classified as a photoheterotroph or a photoautotroph depends on its
A) energy source.
B) carbon source.
C) oxygen requirements.
D) all of the above.
Answer: B
3) In photosynthesis NADH and NADPH are produced by
A) oxidation reactions.
B) reduction reactions.
C) both oxidation and reduction reactions.
D) neither oxidation nor reduction reactions.
Answer: B
4) Photosynthesis is most correctly defined as
A) the production of carbohydrates by a plant or plant-like organism.
B) the conversion of light energy to chemical energy.
C) the absorption of light energy in order to produce carbohydrates.
D) the conversion of carbohydrates into energy yielding organic products.
Answer: B
5) To describe a type of photosynthesis as "oxygenic" implies that
A) oxygen is produced.
B) oxygen is consumed.
C) oxygen functions as a catalyst.
D) none of the above.
Answer: A
6) Which statement is true?
A) The cytochromes contain iron, while chlorophyll contains magnesium.
B) The cytochromes contain magnesium, while chlorophyll contains iron.
C) Both the cytochromes and chlorophyll contain iron but not magnesium.
D) Both the cytochromes and chlorophyll contain magnesium but not iron.
Answer: A
7) Chlorophyll a is green because it
A) absorbs green light and transmits red and blue light.
B) absorbs red and green light and transmits blue light.
C) absorbs red and blue light and transmits green light.
D) absorbs green light and transmits nothing.
Answer: C
8) The carotenoids and the phycobilins
A) are involved in the capture of light energy.
B) function as accessory pigments.
C) are photoprotective.
D) all of the above.
Answer: D
9) Which of the following is/are true about the carotenoids?
A) They have long hydrocarbon chains arranged in a conjugated double bond system.
B) They are usually yellow, red, brown, or green.
C) Although they do not function directly in photophosphorylation, they can transfer energy to the reaction
center to be used in photophosphorylation.
D) All of the above.
Answer: D
10) The master regulatory signal governing transcription of the photosynthetic gene cluster in purple
phototrophic bacteria is
A) H2.
B) O2.
C) CO2.
D) N2.
Answer: B
11) The path of electron flow in oxygenic phototrophs is sometimes referred to as the
A) K scheme.
B) Z scheme.
C) E scheme.
D) Q scheme.
Answer: B
12) Plastocyanin is
A) a membrane bound sac found in certain bacteria.
B) a photosynthetic pigment found in some bacteria.
C) a copper-containing protein that donates electrons in Photosystem II.
D) a blue-green bacterium known for its unusual photoreactive complex.
Answer: C
13) The Calvin Cycle
A) is responsible for the fixation of CO2.
B) utilizes both NADPH and ATP.
C) requires both ribulose bisphosphate carboxylase and phosphoribulokinase.
D) all of the above.
Answer: D
14) Regarding CO2 fixation mechanisms in the green sulfur bacteria,
A) Chlorobium uses the reverse citric acid cycle and Chloroflexus uses the hydroxypropionate pathway.
B) Chlorobium uses the hydroxypropionate pathway and Chloroflexus uses the reverse citric acid cycle.
C) Both Chlorobium and Chloroflexus use the reverse citric acid cycle.
D) Both Chlorobium and Chloroflexus use the hydroxypropionate pathway.
Answer: A
15) In most cases, the final product of sulfur oxidation is
A) hydrogen sulfide.
B) elemental sulfur.
C) sulfate.
D) thiosulfate.
Answer: C
16) The enzymes ammonia monooxygenase and hydroxylamine oxidoreductase are most specifically
associated with
A) nitrification.
B) nitrate oxidation.
C) nitrate reduction.
D) nitrite oxidation.
Answer: A
17) The first step of dissimilative nitrate reduction involves
A) nitrate reductase.
B) nitrite reductase.
C) nitrate oxidase.
D) nitrite oxidase.
Answer: A
18) In terms of oxygen requirements, homoacetogens and methanogens are
A) strict aerobes.
B) strict anaerobes.
C) facultative aerobes.
D) facultative anaerobes.
Answer: B
19) Which of the following metals is/are cofactor(s) in the key enzyme of the acetyl-CoA pathway?
A) Nickel
B) Zinc
C) Iron
D) All of the above
Answer: D
20) The coenzymes F4 2 0 and 7-mercaptoheptanoyl-threonine phosphate (HS-HTP) are __________ in
methanogenesis.
A) electron donors
B) electron recipients
C) electron carriers
D) not involved
Answer: A
21) Central to the mechanism of ATP synthesis is the production of one or another
A) molecular derivatives of a hexose, such as glucose.
B) intermediate isomerases.
C) energy-rich compounds.
D) endergonic intermediaries.
Answer: C
22) Beta oxidation involves
A) the synthesis of a series of two-carbon compounds.
B) the splitting of hexoses into two-carbon units.
C) the cleaving of two-carbon units from fatty acid chains.
D) the production of disaccharides.
Answer: C
23) The utilization of nitrogen gas as a source of nitrogen is called
A) nitrogen reduction.
B) nitrogen fixation.
C) nitrogen oxidation.
D) nitrogen assimilation.
Answer: B
24) The genes for dinitrogenase and dinitrogenase reductase in Klebsiella pneumoniae are part of a complex
regulon known as the
A) nif regulon.
B) fin regulon.
C) nitrolytic regulon.
D) nitro-tif regulon.
Answer: A
25) Definitive proof of N2 fixation is obtained using
A) an isotope of nitrogen, 15N, as a tracer.
B) gas chromatography to assay for nitrogen uptake.
C) electrophoresis to analyze the shifts in nitrogen content.
D) spectrophotometry to measure the opaqueness of possible nitrogen containing substances.
Answer: A
26) What is/are the pigment(s) that is/are obligatory for photosynthesis?
A) Chlorophyll or bacteriochlorophyll
B) Carotenoids
C) Phycoerythrin
D) Phycocyanin
Answer: A
27) Which is not found within the photosynthetic gene cluster of Rhodobacter (a purple phototrophic
bacterium)?
A) Genes encoding proteins that bind pigment molecules in the reaction center and light-harvesting
complexes
B) Genes encoding proteins involved in phycobiliprotein biosynthesis
C) Genes encoding proteins involved in bacteriochlorophyll biosynthesis
D) Genes encoding proteins involved in carotenoid biosynthesis
Answer: B
28) Most chemolithotrophs use what compound as a source of carbon?
A) Glucose
B) Organic sources other than glucose
C) Carbon dioxide
D) Inorganic compounds
Answer: C
29) In organisms undergoing fermentation, the production of what product is energetically advantageous?
A) Hydrogen
B) Pyruvate
C) Glucose
D) Acetate
Answer: D
30) Due to the sensitivity of dinitrogenase reductase, nitrogen fixation must occur under what conditions?
A) Aerobic
B) Psychrophilic
C) Anaerobic
D) Hyperthermophilic
Answer: C
31) In photosynthesis, light energy is conserved as chemical energy.
Answer: TRUE
32) Most phototrophic organisms are also autotrophs.
Answer: TRUE
33) Light energy is used to oxidize CO2 in order to form organic compounds.
Answer: FALSE
34) In the autotrophic reactions of photosynthesis, chemical energy is used to reduce carbon dioxide.
Answer: TRUE
35) Chlorophylls are distinguished by their absorption spectra.
Answer: TRUE
36) Photooxidation reactions can lead to the production of toxic forms of oxygen, and the oxidation and
destruction of the photosynthetic apparatus.
Answer: TRUE
37) Phycobiliproteins are the main light-harvesting pigments of the cyanobacteria and the red algae.
Answer: TRUE
38) Light-mediated ATP synthesis in all phototrophic organisms involves electron transport through a
sequence of electron carriers.
Answer: TRUE
39) Photosystem II absorbs shorter wavelengths, whereas Photosystem I absorbs longer wavelengths.
Answer: TRUE
40) Photosystem I is responsible for splitting a water molecule in the first step of oxygenic electron flow.
Answer: FALSE
41) RubisCO catalyzes the formation of two molecules of 3-phosphoglyceric acid.
Answer: TRUE
42) If an organism is to grow with CO2 as its sole carbon source, it must have energy in the form of ATP as
well as reducing power.
Answer: TRUE
43) H2-oxidizing bacteria are necessarily aerobic.
Answer: FALSE
44) Some hydrogen bacteria have a soluble as well as a membrane-bound hydrogenase.
Answer: TRUE
45) Because H2 levels in oxic environments are transient, it is likely that aerobic hydrogen bacteria shift
between chemoorganotrophy and chemolithotrophy.
Answer: TRUE
46) Most iron-oxidizing bacteria are obligate acidophiles.
Answer: TRUE
47) There are chemotrophic denitrifying bacteria that can couple the oxidation of Fe2+ to the reduction of
NO3– and N2, and can grow under anoxic conditions.
Answer: TRUE
48) N2O can be converted to NO by sunlight.
Answer: TRUE
49) Sulfate reduction can be either assimilative or dissimilative.
Answer: TRUE
50) When lactate or pyruvate is the electron donor during dissimilative sulfate reduction, ATP is produced
from the proton motive force.
Answer: TRUE
51) With few exceptions, autotrophic sulfate reducers use the acetyl-CoA pathway as a means of producing
cell material.
Answer: TRUE
52) Chlorinated compounds can function as electron acceptors for anaerobic respiration in the process
known as oxidative dechlorination.
Answer: FALSE
53) The oxidation-reduction balance referred to when discussing redox reactions is theoretical rather than
real because the numbers of protons and electrons do not necessarily match.
Answer: FALSE
54) Oxygenases are enzymes that catalyze the incorporation of oxygen into organic compounds.
Answer: TRUE
55) The pigments and all the components of the light gathering apparatus are located within systems known
as __________.
Answer: photosynthetic membranes
56) The ultimate low light efficiency structure that functions like a solid state circuit and is found in the green
sulfur bacteria and Chloroflexus is known as the __________.
Answer: chlorosome
57) Phycobiliproteins occurring as high-molecular-weight aggregates are known as __________. Cells with
an increased number of these structures can grow at __________(higher/lower) light intensities.
Answer: phycobilisomes / lower
58) In synthesizing one molecule of glucose from carbon dioxide, __________ molecules of NADPH and
__________ molecules of ATP are required.
Answer: 12 / 18
59) The main means by which gaseous nitrogen is formed biologically is __________.
Answer: denitrification
60) The two methanogenic enzymes responsible for carrying the C1 unit from CO2 to CH4 are __________
and __________.
Answer: methanofuran / methanopterin (either order)
61) TMAO and DMSO are both organic electron __________ which are found in __________
environments.
Answer: acceptors / marine
62) When electron acceptors are not available in anoxic environments, carbon will be catabolized by
__________.
Answer: fermentation
63) __________ is the situation where two different organisms can together degrade some substances that
neither could degrade separately.
Answer: Syntropy
64) __________ is the process involving the addition of an inorganic phosphate which results in the
formation of a hexose phosphate.
Answer: Phosphorolysis
65) The most widespread mechanism required to synthesize glucose in autotrophic organisms is
__________, followed by a reversal of the early steps of __________.
Answer: the Calvin cycle / glycolysis
66) Chemolithotrophic utilization of compounds requires the participation of several specific enzymes. The
oxidation of hydrogen requires the enzyme __________, the oxidation of sulfur requires __________,
__________ participates in the oxidation of iron, and __________ participates in the oxidation of nitrite. The
oxidation of ammonia requires the participation of two enzymes, __________ and __________.
Answer: hydrogenase / sulfite oxidase / rusticyanin / nitrite oxidoreductase / ammonia monooxygenase /
hydroxylamine oxidoreductase (final two may be in either order)
67) Nitrogen fixation is repressed by __________ and __________.
Answer: oxygen / fixed nitrogen
68) Explain the Calvin Cycle process that produces a full molecule of glucose and regenerates the ribulose
bisphosphate molecule.
Answer: Answers will vary.
69) Explain the anammox reaction.
Answer: Answers will vary.
70) Briefly explain three common microbial methods of acetogenesis.
Answer: Answers will vary.
71) Briefly explain the biochemistry of the reduction of CO2 to CH4.
Answer: Answers will vary.
72) What is the difference between an aliphatic hydrocarbon and an aromatic hydrocarbon?
Answer: Answers will vary.
73) Explain the processes involved in the glyoxylate cycle.
Answer: Answers will vary.
74) Explain why it would be advantageous for a photosynthetic microorganism to have more than one type
of chlorophyll or bacteriochlorophyll.
Answer: Answers will vary.