Question 1

Protein turnover of regulatory proteins helps cells to quickly respond to changing conditions.

Accepted Answer

A) True 
 B)False

Question 2

An amino acid formed by transamination of a citric acid cycle intermediate is ________.

Accepted Answer

A)  aspartate
B)  cysteine
C)  serine
D)  alanineE) None of the above
F) All of the above

Question 3

Which of the following is/are true statement(s) about glutamine?

Accepted Answer

A)  It is a nitrogen donor in many biosynthetic reactions.
B)  It is a nitrogen source for glutamate synthase.
C)  It carries nitrogen and carbon between tissues,thus avoiding high toxic levels of NH₄+ in blood.
D)  All of the above.E) B) and C)
F) None of the above

Question 4

The essential amino acids are those that mammals cannot synthesize,but must obtain from the diet.

Accepted Answer

A) True 
 B)False

Question 5

The catabolism of which amino acids can produce sulfuric acid?

Accepted Answer

A)  cysteine and methionine
B)  cysteine and serine
C)  aspartate and glutamate
D)  lysine and arginineE) A) and B)
F) C) and D)

Question 6

The degradation of arginine,histidine and proline all lead to the product ________.

Accepted Answer

A)  pyruvate
B)  acetyl CoA
C)  acetoacetate
D)  glutamateE) A) and B)
F) B) and C)

Question 7

Nitrogenases

Accepted Answer

A)  are protected from oxygen to prevent inactivation.
B)  consist of two protein components.
C)  contain an electron transport system.
D)  A and B only.
E)  All of the above.F) None of the above
G) A) and B)

Question 8

At neutral pH,the main ionic form of ammonia is ________.

Accepted Answer

A)  N₂
B)  NH₄+
C)  NH₃
D)  NH₂-
E)  None of the aboveF) A) and E)
G) A) and D)

Question 9

During the catabolism of amino acids,the carbon skeleton is first degraded,followed by the removal of the amino group.

Accepted Answer

A) True 
 B)False

Question 10

The changes that occur in cells that lead to its death are called ________.

Accepted Answer

A)  cellular necroptosis
B)  programmed lysis
C)  apoptosis
D)  morpholytic degradationE) A) and B)
F) A) and C)

Question 11

Which of the following is/are true concerning transanimation reactions?

Accepted Answer

A)  They can convert α-keto acids to α-amino acids.
B)  All require the coenzyme pyridoxal phosphate.
C)  The catalyzed reactions are near-equilibrium.
D)  All of the above.E) B) and C)
F) A) and B)

Question 12

Most green plants contain both nitrate reductase and nitrite reductase to reduce nitrogen oxides to ammonia.

Accepted Answer

A) True 
 B)False

Question 13

A key precursor in the synthesis of aromatic amino acids (tryptophan,tyrosine and phenylalanine) is ________.

Accepted Answer

A)  prephenate
B)  chorismate
C)  4-hydroxyphenylpyruvate
D)  indoleE) All of the above
F) A) and B)

Question 14

Tryptophan synthase's a subunit catalyzes the cleavage of indole glycerol phosphate to glyceralde 3-phosphate and indole.

Accepted Answer

A) True 
 B)False

Question 15

Amino acids that are degraded to pyruvate or citric acid cycle intermediates are called ketogenic.

Accepted Answer

A) True 
 B)False

Question 16

The enzyme ________ is one of the most abundant in liver mitochondria and catalyzes the synthesis of the molecule shown below.

Accepted Answer

A)  arginase
B)  carbamoyl phosphate synthetase I
C)  4-α-carbinolamine dehydratase
D)  transaminaseE) All of the above
F) B) and C)

Question 17

What type of reaction is shown below? Amino acid + α-Ketoglutarate⇋ α-Keto acid + Glutamate

Accepted Answer

A)  Reductive amination.
B)  Oxidation.
C)  Transamination.
D)  Hydrolysis.E) A) and C)
F) A) and B)

Question 18

Most animals and plants can tolerate moderately high cellular concentrations of ammonia;however,unusable excess is generally eliminated via the urea cycle.

Accepted Answer

A) True 
 B)False

Question 19

Transamination reactions require which coenzyme?

Accepted Answer

A)  Pyridoxal phosphate.
B)  Thiamine pyrophosphate.
C)  Adensosine triphosphate.
D)  Flavin mononucleotide.E) All of the above
F) A) and D)

Question 20

Chorismate is a key branch-point intermediate in aromatic amino acid synthesis.

Accepted Answer

A) True 
 B)False

Exam 17: Amino Acid Metabolism

Amino acids that are degraded to pyruvate or citric acid cycle intermediates are called ketogenic.

Correct AnswerverifiedShow Answer

Nitrogenases

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The degradation of arginine,histidine and proline all lead to the product ________.

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Which of the following is/are true concerning transanimation reactions?

Correct AnswerverifiedShow Answer

Chorismate is a key branch-point intermediate in aromatic amino acid synthesis.

Correct AnswerverifiedShow Answer

An amino acid formed by transamination of a citric acid cycle intermediate is ________.

Correct AnswerverifiedShow Answer

The changes that occur in cells that lead to its death are called ________.

Correct AnswerverifiedShow Answer

What type of reaction is shown below? Amino acid + α-Ketoglutarate⇋ α-Keto acid + Glutamate

Correct AnswerverifiedShow Answer

At neutral pH,the main ionic form of ammonia is ________.

Correct AnswerverifiedShow Answer

Most animals and plants can tolerate moderately high cellular concentrations of ammonia;however,unusable excess is generally eliminated via the urea cycle.

Correct AnswerverifiedShow Answer

The catabolism of which amino acids can produce sulfuric acid?

Correct AnswerverifiedShow Answer

The essential amino acids are those that mammals cannot synthesize,but must obtain from the diet.

Correct AnswerverifiedShow Answer

Which of the following is/are true statement(s) about glutamine?

Correct AnswerverifiedShow Answer

The enzyme ________ is one of the most abundant in liver mitochondria and catalyzes the synthesis of the molecule shown below.

Correct AnswerverifiedShow Answer

Transamination reactions require which coenzyme?

Correct AnswerverifiedShow Answer

A key precursor in the synthesis of aromatic amino acids (tryptophan,tyrosine and phenylalanine) is ________.

Correct AnswerverifiedShow Answer

During the catabolism of amino acids,the carbon skeleton is first degraded,followed by the removal of the amino group.

Correct AnswerverifiedShow Answer

Protein turnover of regulatory proteins helps cells to quickly respond to changing conditions.

Correct AnswerverifiedShow Answer

Tryptophan synthase's a subunit catalyzes the cleavage of indole glycerol phosphate to glyceralde 3-phosphate and indole.

Correct AnswerverifiedShow Answer

Most green plants contain both nitrate reductase and nitrite reductase to reduce nitrogen oxides to ammonia.

Correct AnswerverifiedShow Answer

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