Question 1

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)   hydrolysisE) A) and B)
F) B) and C)

Question 2

The proteases responsible for cell death are called . They cleave on the carboxyl side of residues.

Accepted Answer

A)   caspases; aspartate
B)   typsins; lysine and arginine
C)   carnitines; cysteine
D)   ureases; uridineE) B) and D)
F) A) and B)

Question 3

Physiological roles for glutamate dehydrogenase include all of the following, except

Accepted Answer

A)   the generation of glutamate when NH4+ is present at high concentrations in E. coli.
B)   the conversion of glutamate to glutamine in most organisms.
C)   the use of an NADPH-dependent enzyme for reductive amination in Neurospora crassa.
D)   the degradation of amino acids and generation of NH4+ in mammals.E) A) and B)
F) None of the above

Question 4

The degradation of which amino acid requires the coenzyme tetrahydrofolate?

Accepted Answer

A)   histidine
B)   serine
C)   leucine
D)   alanineE) B) and C)
F) All of the above

Question 5

Which of the following amino acids is/are derived from 3-phosphoglycerate?

Accepted Answer

A)   serine
B)   glycine
C)   cysteine
D)   All of the aboveE) B) and C)
F) None of the above

Question 6

Glycine is a precursor for all of the following except

Accepted Answer

A)   cytidine.
B)   creatine phosphate.
C)   porphobilinogen.
D)   bile salts.
E)   glyoxylate.F) A) and B)
G) B) and D)

Question 7

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)   4a-carbinolamine dehydratase
D)   transaminaseE) B) and C)
F) A) and D)

Question 8

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

Accepted Answer

A) True 
 B)False

Question 9

Which of the following is/are true statements)  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 aboveE) A) and B)
F) A) and C)

Question 10

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 11

The carbon in urea originates from .

Accepted Answer

A)   aspartate
B)   ornithine
C)   bicarbonate
D)   ATPE) C) and D)
F) None of the above

Question 12

Which statements)  apply to urea?

Accepted Answer

A)   highly soluble in water
B)   produced in the liver
C)   major solute in urine of mammals
D)   compound used as a means of removing excess nitrogen
E)   All of the aboveF) A) and C)
G) A) and E)

Question 13

Industrially, nitrogen for use in fertilizers is converted to ammonia by .

Accepted Answer

A)   a simple, energy efficient reaction of N2 with water
B)   a cryogenic very low temperature)  process between N2 and H2
C)   special catalysts which drive the reduction of N2 by H2
D)   a reaction between nitric acid and hydrogen gasE) B) and C)
F) C) and D)

Question 14

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 aboveF) A) and C)
G) All of the above

Question 15

In animals glutamate synthase is essential for the production of glutamate.

Accepted Answer

A) True 
 B)False

Question 16

In the urea cycle which molecule is transported from the mitochondrial matrix to the cytosol as ornithine is transported in the opposite direction?

Accepted Answer

A)   arginine
B)   citrulline
C)   glutamate
D)   carnitineE) B) and C)
F) C) and D)

Question 17

Transamination reactions require which coenzyme?

Accepted Answer

A)   PLP
B)   TPP
C)   ATP
D)   FMNE) A) and B)
F) B) and D)

Question 18

Phenylketonuria PKU)  is a disease caused by a defect in formation.

Accepted Answer

A)   phenylalanine
B)   a-ketoglutarate
C)   tyrosine
D)   ureaE) None of the above
F) A) and D)

Question 19

Carbamoyl phosphate synthetase

Accepted Answer

A)   is an essential precursor in pyrimidine biosynthesis.
B)   catalyzes the synthesis of carbamoyl phosphate from bicarbonate and glutamine.
C)   is one of the most abundant enzymes in liver mitochondria.
D)   A and B only
E)   All of the aboveF) B) and E)
G) B) and D)

Question 20

Virtually all of the nitrogen used in metabolism comes directly from nitrogen fixation.

Accepted Answer

A) True 
 B)False

Exam 17: Amino Acid Metabolism

Industrially, nitrogen for use in fertilizers is converted to ammonia by .

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Physiological roles for glutamate dehydrogenase include all of the following, except

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Nitrogenases

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

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Transamination reactions require which coenzyme?

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Carbamoyl phosphate synthetase

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In the urea cycle which molecule is transported from the mitochondrial matrix to the cytosol as ornithine is transported in the opposite direction?

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In animals glutamate synthase is essential for the production of glutamate.

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Which of the following amino acids is/are derived from 3-phosphoglycerate?

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The proteases responsible for cell death are called . They cleave on the carboxyl side of residues.

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Virtually all of the nitrogen used in metabolism comes directly from nitrogen fixation.

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

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

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Which of the following is/are true statements) about glutamine?

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The degradation of which amino acid requires the coenzyme tetrahydrofolate?

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The carbon in urea originates from .

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

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Glycine is a precursor for all of the following except

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Phenylketonuria PKU) is a disease caused by a defect in formation.

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Which statements) apply to urea?

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

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