Question 1

Write a mechanism for the nonenzymatic transformation of glutamate semialdehyde into 1-pyrroline-5-carboxylate. Which amino acid is synthesized from 1-pyrroline-5-carboxylate in vivo?

Accepted Answer

proline is synthesized from 1-pyrroline-5-carboxylate.

Question 2

Draw the structure of the product formed when the substance shown below undergoes amide formation.

Accepted Answer

The answer of Draw the structure of the product formed...

Question 3

Which of the following is not an intermediate in the urea cycle?

Accepted Answer

A)   arginine
B)   citrulline
C)   ornithine
D)   lysineE) B) and C)
F) A) and D)

Question 4

This many ATP equivalents are required to produce one molecule of urea from ammonia:

Accepted Answer

A)   One ATP equivalent.
B)   Two ATP equivalents.
C)   Three ATP equivalents.
D)   Four ATP equivalents.
E)   Six ATP equivalents.F) C) and D)
G) C) and E) C

Question 5

The formation of amino acids from proteins

Accepted Answer

A)   occurs during anabolism.
B)   is endergonic.
C)   occurs during digestion.
D)   is a cellular process.
E)   all of theseF) B) and D)
G) A) and E)

Question 6

The reaction, 2 NH4+ + α-ketoglutarate + NADPH + ATP → glutamine + NADP+ + ADP + Pi + H2O, is the combined result of what two enzymes?

Accepted Answer

A)   nitrogenase and glutamate dehydrogenase (GDH) 
B)   GDH and glutamine synthetase (GS) 
C)   GS and nitrogenase
D)   GDH and nitrogenase
E)   all of these are correctF) C) and E)
G) A) and E)

Question 7

The coenzyme pyridoxal phosphate (PLP)  in its active form has all the following characteristics except:

Accepted Answer

A)   It is covalently bonded to its enzyme.
B)   It possesses a phosphate group.
C)   It bonds to an amine group by means of the phosphate group.
D)   All of these characteristics are true.
E)   All of these characteristics are false.F) D) and E)
G) A) and E)

Question 8

What amino acid is the following α-keto acid derived from?

Accepted Answer

The answer of What amino acid is the following α-keto...

Question 9

Suppose that the formation of a dipeptide is endergonic by +14.7 kJ/mol. If this reaction is coupled with the hydrolysis of ATP, will the net reaction be spontaneous or nonspontaneous? Explain your answer.

Accepted Answer

The net reaction will be spontaneous since the ΔG_net value is −15.8 kJ/mol. This is based on coupling the endergonic reaction with a ΔG of +14.7 kJ/mol with the exergonic hydrolysis of ATP with a ΔG value of −30.5 kJ/mol. ΔG_net = −30.5 kJ/mol +14.7 kJ/mol = −15.8 kJ/mol.

Question 10

In the process of amino acid biosynthesis, how are glutamic acid, glutamine, proline, and arginine all related?

Accepted Answer

A)   They are all derived from α-ketoglutarate.
B)   They are all derivatives of acetyl CoA.
C)   They are all derivatives of pyruvate.
D)   They are all derived from aspartate.
E)   They are all derivatives of 3-phosphoglycerate.F) A) and C)
G) A) and B)

Question 11

The key functional group in the PLP-dependent transamination of an α-amino acid is an activated

Accepted Answer

A)   amine
B)   imine
C)   amide
D)   enamineE) B) and C)
F) A) and D)

Question 12

The following shows a part of the biosynthetic pathway of amino acids. If possible, draw an arrow to match the amino acid with its precursor.

Accepted Answer

The answer of The following shows a part of the...

Question 13

Glucogenic amino acids include all of the following, except:

Accepted Answer

A)   Glycine
B)   Alanine
C)   Aspartic acid
D)   Leucine
E)   All of these amino acids are glucogenic.F) C) and D)
G) B) and C)

Question 14

What product would be obtained from enzymatic transamination of 3-hydroxy-2-ketopropanoic acid?

Accepted Answer

The answer of What product would be obtained from enzymatic...

Question 15

Consider the deamination of serine to answer the following questions.
a)Draw the structure of the α-keto acid produced by the deamination of serine.
b)What is the fate of the amino group in serine when this conversion occurs in a mammalian system?

Accepted Answer

a) <img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30"> b)The amino group is remov...

Question 16

What reaction does glutamate dehydrogenase (GDH)  catalyze?

Accepted Answer

A)   The oxidative deamination of glutamate to yield α-ketoglutarate.
B)   Phosphorylation of carbamate to yield carbamoyl phosphate.
C)   The amidation of the γ carboxyl group of glutamate to form glutamine.
D)   The deadenylation of glutamine synthetase (GS) .
E)   The adenylation of glutamine synthetase.F) A) and B)
G) B) and D)

Question 17

Aspartate is formed from transamination of:

Accepted Answer

A)   asparagine
B)   aspartame
C)   oxaloacetate
D)   citrate
E)   α-ketoglutarateF) B) and C)
G) B) and E)

Question 18

3-Phosphoglycerate contains the carbon skeleton used to make

Accepted Answer

A)   serine
B)   cysteine
C)   glycine
D)   all of theseE) C) and D)
F) A) and D)

Question 19

Ornithine serves three metabolically important roles but is not found in proteins. Which of the following statements about ornithine is not true?

Accepted Answer

A)   It is a precursor in the synthesis of citrulline.
B)   It is an intermediate in the urea cycle.
C)   It is a precursor in the synthesis of arginine.
D)   It is biosynthesized from glutamine.
E)   It is a product of arginine hydrolysis.F) All of the above
G) None of the above

Question 20

Amino acids biosynthesized from aspartate include all except:

Accepted Answer

A)   asparagine
B)   threonine
C)   methionine
D)   lysine
E)   glutamateF) C) and D)
G) None of the above

Exam 20: Amino Acid Metabolism

Write a mechanism for the nonenzymatic transformation of glutamate semialdehyde into 1-pyrroline-5-carboxylate. Which amino acid is synthesized from 1-pyrroline-5-carboxylate in vivo?

Correct Answer
verified
11eab600_0803_23b7_9625_8fdbd0184057_TB6688_00 proline is synthesized from 1-pyrroline-5-carboxylate.

Draw the structure of the product formed when the substance shown below undergoes amide formation.

Correct Answer
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Which of the following is not an intermediate in the urea cycle?

Correct Answer
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This many ATP equivalents are required to produce one molecule of urea from ammonia:

Correct Answer
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C

The formation of amino acids from proteins

Correct Answer
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The reaction, 2 NH₄⁺ + α-ketoglutarate + NADPH + ATP → glutamine + NADP⁺ + ADP + P_i + H₂O, is the combined result of what two enzymes?

Correct Answer
verified

The coenzyme pyridoxal phosphate (PLP) in its active form has all the following characteristics except:

Correct Answer
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What amino acid is the following α-keto acid derived from?

Correct Answer
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Suppose that the formation of a dipeptide is endergonic by +14.7 kJ/mol. If this reaction is coupled with the hydrolysis of ATP, will the net reaction be spontaneous or nonspontaneous? Explain your answer.

In the process of amino acid biosynthesis, how are glutamic acid, glutamine, proline, and arginine all related?

Correct Answer
verified

The key functional group in the PLP-dependent transamination of an α-amino acid is an activated

Correct Answer
verified

The following shows a part of the biosynthetic pathway of amino acids. If possible, draw an arrow to match the amino acid with its precursor.

Correct Answer
verified

Glucogenic amino acids include all of the following, except:

Correct Answer
verified

What product would be obtained from enzymatic transamination of 3-hydroxy-2-ketopropanoic acid?

Correct Answer
verified

Consider the deamination of serine to answer the following questions. a)Draw the structure of the α-keto acid produced by the deamination of serine. b)What is the fate of the amino group in serine when this conversion occurs in a mammalian system?

Correct Answer
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a) b)The amino group is remov...
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What reaction does glutamate dehydrogenase (GDH) catalyze?

Correct Answer
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Aspartate is formed from transamination of:

Correct Answer
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3-Phosphoglycerate contains the carbon skeleton used to make

Correct Answer
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Ornithine serves three metabolically important roles but is not found in proteins. Which of the following statements about ornithine is not true?

Correct Answer
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Amino acids biosynthesized from aspartate include all except:

Correct Answer
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Exam 20: Amino Acid Metabolism

Write a mechanism for the nonenzymatic transformation of glutamate semialdehyde into 1-pyrroline-5-carboxylate. Which amino acid is synthesized from 1-pyrroline-5-carboxylate in vivo?

Correct Answerverified11eab600_0803_23b7_9625_8fdbd0184057_TB6688_00 proline is synthesized from 1-pyrroline-5-carboxylate.

Draw the structure of the product formed when the substance shown below undergoes amide formation.

Correct AnswerverifiedShow Answer

Which of the following is not an intermediate in the urea cycle?

Correct AnswerverifiedShow Answer

This many ATP equivalents are required to produce one molecule of urea from ammonia:

Correct AnswerverifiedC

The formation of amino acids from proteins

Correct AnswerverifiedShow Answer

The reaction, 2 NH4+ + α-ketoglutarate + NADPH + ATP → glutamine + NADP+ + ADP + Pi + H2O, is the combined result of what two enzymes?

Correct AnswerverifiedShow Answer

The coenzyme pyridoxal phosphate (PLP) in its active form has all the following characteristics except:

Correct AnswerverifiedShow Answer

What amino acid is the following α-keto acid derived from?

Correct AnswerverifiedShow Answer

Suppose that the formation of a dipeptide is endergonic by +14.7 kJ/mol. If this reaction is coupled with the hydrolysis of ATP, will the net reaction be spontaneous or nonspontaneous? Explain your answer.

In the process of amino acid biosynthesis, how are glutamic acid, glutamine, proline, and arginine all related?

Correct AnswerverifiedShow Answer

The key functional group in the PLP-dependent transamination of an α-amino acid is an activated

Correct AnswerverifiedShow Answer

The following shows a part of the biosynthetic pathway of amino acids. If possible, draw an arrow to match the amino acid with its precursor.

Correct AnswerverifiedShow Answer

Glucogenic amino acids include all of the following, except:

Correct AnswerverifiedShow Answer

What product would be obtained from enzymatic transamination of 3-hydroxy-2-ketopropanoic acid?

Correct AnswerverifiedShow Answer

Consider the deamination of serine to answer the following questions. a)Draw the structure of the α-keto acid produced by the deamination of serine. b)What is the fate of the amino group in serine when this conversion occurs in a mammalian system?

Correct Answerverifieda) b)The amino group is remov...View AnswerShow Answer

What reaction does glutamate dehydrogenase (GDH) catalyze?

Correct AnswerverifiedShow Answer

Aspartate is formed from transamination of:

Correct AnswerverifiedShow Answer

3-Phosphoglycerate contains the carbon skeleton used to make

Correct AnswerverifiedShow Answer

Ornithine serves three metabolically important roles but is not found in proteins. Which of the following statements about ornithine is not true?

Correct AnswerverifiedShow Answer

Amino acids biosynthesized from aspartate include all except:

Correct AnswerverifiedShow Answer

Correct Answer
verified
11eab600_0803_23b7_9625_8fdbd0184057_TB6688_00 proline is synthesized from 1-pyrroline-5-carboxylate.

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C

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The reaction, 2 NH₄⁺ + α-ketoglutarate + NADPH + ATP → glutamine + NADP⁺ + ADP + P_i + H₂O, is the combined result of what two enzymes?

Correct Answer
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a) b)The amino group is remov...
View Answer

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