CH. 22 LEHNINGER BIOCHEM TEST BANK
1. 1. Which of the following statements about the fixation of atmospheric
nitrogen (N2) into NH3 by living cells is false?
A) It involves the transfer of eight electrons per mol of N2.
B) It occurs in certain microorganisms, but not in humans.
C) It requires a source of electrons, normally ferredoxin.
D) It requires one ATP per mol of N2 fixed.
E) It requires two key protein components, each containing iron.: D
2. 2. Which of the following is not true about the anammox reaction?
A) Anammox converts ammonia to nitrogen.
B) Anammox is performed by symbiotic bacteria of leguminous plants.
C) Anammox generates the highly reactive molecule hydrazine that is a com-
ponent of rocket fuel.
D) Anammox occursw anaerobically.
E) The ultimate electron acceptor in anammox is nitrite.: B
3. 3. Which of the following enzymes is not involved in the assimilation of
inorganic nitrogen into an organic molecule?
A) Dinitrogenase reductase
B) Nitrate reductase
C) Nitrite reductase
D) Nitrile reductase
E) Dinitrogenase: D
4. 4. Which of the following enzymes is not involved in the assimilation of
inorganic nitrogen into an organic molecule?
A) Arginase
B) Glutamate dehydrogenase
C) Glutamate synthase
D) Glutamine synthetase
E) Dinitrogenase: A
5. 5. The enzymatic machinery to fix atmospheric N2 into NH4+ is:
A) a means of producing ATP when excess N2 is available.
B) composed of two key proteins, each containing iron.
C) relatively stable when exposed to O2.
D) specific to plant cells.
E) unaffected by the supply of electrons.: B
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, CH. 22 LEHNINGER BIOCHEM TEST BANK
6. 6. Glutamine synthetase converts to whereas glutamate syn-
thase converts to .
A) formate; glutamine; ammonia; glutamate
B) asparagine; glutamine; -ketoglutarate; glutamate
C) alpha-ketoglutarate; glutamine; oxaloacetic acid; glutamate
D) alpha-ketoglutarate; glutamine; alpha-ketoglutarate; glutamate
E) glutamate; glutamine; alpha-ketoglutarate; glutamate: E
7. 7. Which of the following is not true about glutamine amidotransferases?
A) These enzymes proceed via a covalent intermediate.
B) Ammonia is released into a channel.
C) Glutamate is a product of the reaction.
D) ATP is needed to activate the glutamine.
E) A Cys at the active site is critical for the activity of these enzymes.: D
8. 8. Nonessential amino acids:
A) are amino acids other than those required for protein synthesis.
B) are not utilized in mammalian proteins.
C) are synthesized by plants and bacteria, but not by humans.
D) can be synthesized in humans as well as in bacteria.
E) may be substituted with other amino acids in proteins.: D
9. 9. An amino acid that does not derive its carbon skeleton, at least in part,
from alpha-ketoglutarate is:
A) arginine.
B) glutamate.
C) glutamine.
D) proline.
E) threonine.: E
10. 10. Glutamine, arginine, and proline:
A) do not have a common precursor.
B) may all be derived from a citric acid cycle intermediate.
C) may all be derived from a Cori cycle intermediate.
D) may all be derived from a glycolytic intermediate.
E) may all be derived from a urea cycle intermediate.: B
11. 11. In which group are all the amino acids closely interrelated metabolical-
ly?
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1. 1. Which of the following statements about the fixation of atmospheric
nitrogen (N2) into NH3 by living cells is false?
A) It involves the transfer of eight electrons per mol of N2.
B) It occurs in certain microorganisms, but not in humans.
C) It requires a source of electrons, normally ferredoxin.
D) It requires one ATP per mol of N2 fixed.
E) It requires two key protein components, each containing iron.: D
2. 2. Which of the following is not true about the anammox reaction?
A) Anammox converts ammonia to nitrogen.
B) Anammox is performed by symbiotic bacteria of leguminous plants.
C) Anammox generates the highly reactive molecule hydrazine that is a com-
ponent of rocket fuel.
D) Anammox occursw anaerobically.
E) The ultimate electron acceptor in anammox is nitrite.: B
3. 3. Which of the following enzymes is not involved in the assimilation of
inorganic nitrogen into an organic molecule?
A) Dinitrogenase reductase
B) Nitrate reductase
C) Nitrite reductase
D) Nitrile reductase
E) Dinitrogenase: D
4. 4. Which of the following enzymes is not involved in the assimilation of
inorganic nitrogen into an organic molecule?
A) Arginase
B) Glutamate dehydrogenase
C) Glutamate synthase
D) Glutamine synthetase
E) Dinitrogenase: A
5. 5. The enzymatic machinery to fix atmospheric N2 into NH4+ is:
A) a means of producing ATP when excess N2 is available.
B) composed of two key proteins, each containing iron.
C) relatively stable when exposed to O2.
D) specific to plant cells.
E) unaffected by the supply of electrons.: B
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, CH. 22 LEHNINGER BIOCHEM TEST BANK
6. 6. Glutamine synthetase converts to whereas glutamate syn-
thase converts to .
A) formate; glutamine; ammonia; glutamate
B) asparagine; glutamine; -ketoglutarate; glutamate
C) alpha-ketoglutarate; glutamine; oxaloacetic acid; glutamate
D) alpha-ketoglutarate; glutamine; alpha-ketoglutarate; glutamate
E) glutamate; glutamine; alpha-ketoglutarate; glutamate: E
7. 7. Which of the following is not true about glutamine amidotransferases?
A) These enzymes proceed via a covalent intermediate.
B) Ammonia is released into a channel.
C) Glutamate is a product of the reaction.
D) ATP is needed to activate the glutamine.
E) A Cys at the active site is critical for the activity of these enzymes.: D
8. 8. Nonessential amino acids:
A) are amino acids other than those required for protein synthesis.
B) are not utilized in mammalian proteins.
C) are synthesized by plants and bacteria, but not by humans.
D) can be synthesized in humans as well as in bacteria.
E) may be substituted with other amino acids in proteins.: D
9. 9. An amino acid that does not derive its carbon skeleton, at least in part,
from alpha-ketoglutarate is:
A) arginine.
B) glutamate.
C) glutamine.
D) proline.
E) threonine.: E
10. 10. Glutamine, arginine, and proline:
A) do not have a common precursor.
B) may all be derived from a citric acid cycle intermediate.
C) may all be derived from a Cori cycle intermediate.
D) may all be derived from a glycolytic intermediate.
E) may all be derived from a urea cycle intermediate.: B
11. 11. In which group are all the amino acids closely interrelated metabolical-
ly?
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