Question 1

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 C)
F) All of the above

Question 2

In mammals,most amino acids undergo deamination in the ________.

Accepted Answer

A)  liver
B)  kidney
C)  pancreas
D)  mitochondria of all cell typesE) B) and C)
F) A) and C) A

Question 3

Nitrogenase catalyzes the reduction of N₂ to nitrate.

Accepted Answer

A) True 
 B)False

Question 4

Which of these types of proteins are likely to have short half-life and be specifically targeted for degradation?

Accepted Answer

A)  Hormone protein.
B)  Mutated (abnormal protein) .
C)  Transport protein.
D)  Structural protein.E) A) and B)
F) A) and C)

Question 5

A large percentage of nitrogen,undergoing metabolism,comes from nitrogen fixation.

Accepted Answer

A) True 
 B)False  False

Question 6

Which is not produced from the degradation of branched-chain amino acids?

Accepted Answer

A)  Succinyl CoA.
B)  Acetyl CoA.
C)  Malonyl CoA.
D)  Propionyl CoA.E) C) and D)
F) A) and B)

Question 7

Periportal cells of the liver are nearest to the inflow of blood and have a higher capacity for urea synthesis than the perivenous cells that are near the outflow.

Accepted Answer

A) True 
 B)False

Question 8

Defects in which of the following may result in elevated levels of phenylalanine?

Accepted Answer

A)  Deficiencies in dihydropteridine reductase.
B)  Deficiencies in 4a-carbinolamine dehydratase.
C)  Defects in the biosynthesis of tetrahydrobiopterin.
D)  All of the above.E) All of the above
F) None of the above

Question 9

Which of the following is an amide-containing amino acid?

Accepted Answer

A)  Alanine.
B)  Arginine.
C)  Aspartate.
D)  Asparagine.E) A) and C)
F) A) and D)

Question 10

Ammonia is incorporated into amino acids via which of the following?

Accepted Answer

A)  Glutamate.
B)  Glutamine.
C)  Carbamoyl phosphate.
D)  All of the above.E) None of the above
F) B) and D)

Question 11

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)  Carnitine.E) None of the above
F) A) and B)

Question 12

Aspartate is the precursor for which of the following amino acids?

Accepted Answer

A)  Lysine.
B)  Threonine.
C)  Methionine.
D)  All of the above.E) None of the above
F) All of the above D

Question 13

What would be the product of the transamination of the structure shown below? (The unionized forms are shown. )

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) A) and D)
F) A) and C)

Question 14

Malignant lymphocytes of patients with acute lymphoblastic leukemia can be treated with injections of bacterial asparaginase because

Accepted Answer

A)  the levels of asparagine in malignant cells is too high.
B)  this reduces the levels of asparagine in blood plasma and that starves malignant cells.
C)  this increases the levels of asparagine in blood plasma and this promotes destruction of malignant cells.
D)  the levels of asparagine in malignant cells is too low.E) B) and D)
F) C) and D)

Question 15

The disease alcaptonuria is caused by a defect in the kidney transport of cysteine.

Accepted Answer

A) True 
 B)False

Question 16

Microorganisms capable of fixing nitrogen into a form usable by animals obtain the energy for this process from ________.

Accepted Answer

A)  lightning
B)  oxidation and reduction (respiration) 
C)  photosynthesis of host plants
D)  soil nutrientsE) A) and D)
F) A) and C)

Question 17

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) C) and D)
F) A) and D)

Question 18

Mammalian carbamoyl phosphate synthetase I

Accepted Answer

A)  is one of the most abundant enzymes in liver mitochondria.
B)  is involved in the urea cycle.
C)  catalyzes the synthesis of carbamoyl phosphate from bicarbonate and ammonia.
D)  A and B only.
E)  All of the above.F) A) and E)
G) B) and D)

Question 19

Glutamine is metabolised to biocarbonate ion in the ________ to replenish this important component of the blood buffering system.

Accepted Answer

A)  liver
B)  kidneys
C)  red blood cells
D)  muscle tissueE) B) and C)
F) B) and D)

Question 20

Nitric oxide is produced from which reaction?

Accepted Answer

A)  Arginine to citrulline.
B)  Glutamate to α-ketoglutarate.
C)  Bicarbonate to carbamoyl phosphate.
D)  Tryptophan to acetyl CoA.E) None of the above
F) A) and B)

Exam 17: Amino Acid Metabolism

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

Correct AnswerverifiedShow Answer

In mammals,most amino acids undergo deamination in the ________.

Correct AnswerverifiedA

Nitrogenase catalyzes the reduction of N₂ to nitrate.

Correct AnswerverifiedShow Answer

Which of these types of proteins are likely to have short half-life and be specifically targeted for degradation?

Correct AnswerverifiedShow Answer

A large percentage of nitrogen,undergoing metabolism,comes from nitrogen fixation.

Correct AnswerverifiedFalse

Which is not produced from the degradation of branched-chain amino acids?

Correct AnswerverifiedShow Answer

Periportal cells of the liver are nearest to the inflow of blood and have a higher capacity for urea synthesis than the perivenous cells that are near the outflow.

Correct AnswerverifiedShow Answer

Defects in which of the following may result in elevated levels of phenylalanine?

Correct AnswerverifiedShow Answer

Which of the following is an amide-containing amino acid?

Correct AnswerverifiedShow Answer

Ammonia is incorporated into amino acids via which of the following?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Aspartate is the precursor for which of the following amino acids?

Correct AnswerverifiedD

What would be the product of the transamination of the structure shown below? (The unionized forms are shown. )

Correct AnswerverifiedShow Answer

Malignant lymphocytes of patients with acute lymphoblastic leukemia can be treated with injections of bacterial asparaginase because

Correct AnswerverifiedShow Answer

The disease alcaptonuria is caused by a defect in the kidney transport of cysteine.

Correct AnswerverifiedShow Answer

Microorganisms capable of fixing nitrogen into a form usable by animals obtain the energy for this process from ________.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Mammalian carbamoyl phosphate synthetase I

Correct AnswerverifiedShow Answer

Glutamine is metabolised to biocarbonate ion in the ________ to replenish this important component of the blood buffering system.

Correct AnswerverifiedShow Answer

Nitric oxide is produced from which reaction?

Correct AnswerverifiedShow Answer

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False

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D

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