Chapter 22 Testbank - Chapter 22 Biosynthesis of Amino...

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Chapter 22 Biosynthesis of Amino Acids, Nucleotides, and Related Molecules Multiple Choice Questions 1. Overview of nitrogen metabolism Pages: 854-855 Difficulty: 2 Ans: D Which of the following statements about the fixation of atmospheric nitrogen (N 2 ) into NH 3 by living cells is false ? A) It involves the transfer of 8 electrons per mol of N 2 . 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 N 2 fixed. E) It requires two key protein components, each containing iron. 2. Overview of nitrogen metabolism Pages: 854-858 Difficulty: 2 Ans: A 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) Nitrogenase 3. Overview of nitrogen metabolism Pages: 854-855 Difficulty: 2 Ans: B The enzymatic machinery to fix atmospheric N 2 into NH 4 + is: A) a means of producing ATP when excess N 2 is available. B) composed of two key proteins, each containing iron. C) relatively stable when exposed to O 2 . D) specific to plant cells. E) unaffected by the supply of electrons. 4. Biosynthesis of amino acids Pages: 860-861 Difficulty: 2 Ans: C Erythrose 4-phosphate is a precursor of: A) aspartate. B) cysteine. C) phenylalanine. D) serine. E) threonine.
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Chapter 22 Biosynthesis of Amino Acids, Nucleotides, and Related Molecules 5. Biosynthesis of amino acids Pages: 860-861 Difficulty: 2 Ans: D 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. 6. Biosynthesis of amino acids Page: 861 Difficulty: 3 Ans: E An amino acid that does not derive its carbon skeleton, at least in part, from α -ketoglutarate is: A) arginine. B) glutamate. C) glutamine. D) proline. E) threonine. 7. Biosynthesis of amino acids Page: 861 Difficulty: 3 Ans: B 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. 8. Biosynthesis of amino acids Page: 862 Difficulty: 2 Ans: E In which group are all the amino acids closely interrelated metabolically? A) Arginine, hydroxyproline, and histidine B) Arginine, tyrosine, and glutamate C) Glycine, valine, glutamine, and aspartate D) Ornithine, alanine, glycine, and valine E) Ornithine, proline, arginine, and glutamate 9. Biosynthesis of amino acids Page: 863 Difficulty: 2 Ans: D If glucose labeled with 14 C at C-1 were the starting material for amino acid biosynthesis, the product(s) that would be readily formed is (are):
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This note was uploaded on 04/14/2010 for the course BHC 3023 taught by Professor Harmen during the Spring '10 term at University of South Florida.

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Chapter 22 Testbank - Chapter 22 Biosynthesis of Amino...

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