Deck 11: Amine Metabolism

Question 1

_____ are involved in the nonselective degradation of milk proteins in neonates.

Answer 1

Lysosomes

Question 2

Which of the following organisms excrete uric acid?

A) birds
B) reptiles
C) jellyfish
D) A and B
E) all of the above

Answer 2

A and B

Question 3

What do birds excrete as nitrogen waste instead of urea?

A) asparagine
B) uric acid
C) carbamoyl phosphate
D) citrulline
E) arginine

Answer 3

uric acid

Question 4

What type of reaction is used to deaminate amino acids, resulting in a new amino acid and a new $\alpha$ -keto acid?

A) ATP-dependent ligation
B) transamination
C) oxidation
D) condensation
E) reduction

Question 5

Glutamate undergoes a(n) _____, catalyzed by glutamate dehydrogenase, to yield $\alpha$ -ketoglutarate, NADH, and _____.

A) reductive deamination; water
B) oxidative deamination; ammonia
C) reductive amination; water
D) oxidative amination; ammonia
E) none of the above

Question 6

The amino acid _____ has been thought to act as a transfer system for NH₃, safely allowing the toxic molecule to be transported from the liver to the kidneys.

Question 7

The enzyme ______ is critical to regulating nitrogen metabolism.

Question 8

In high levels, ammonia is toxic to _____ cells.

A) kidney
B) cardiac
C) liver
D) nerve
E) intestinal

Question 9

In the mechanism of carbamoyl phosphate synthetase, what undergoes nucleophilic attack by ammonia?

A) the carbonyl group of carboxyphosphate
B) the terminal phosphate of ATP
C) the middle phosphate of ATP
D) the carbonyl group of carbamate
E) the phosphate of carboxyphosphate

Question 10

Which of the following contains the correct sequence of reactants for carbamoyl phosphate synthetase?

A) ATP and ammonia, then bicarbonate, then ATP
B) ATP and ammonia, then ATP, then bicarbonate
C) ATP and bicarbonate, then ammonia, then ATP
D) ATP and bicarbonate, then ATP, then ammonia
E) ammonia and bicarbonate, then two ATP molecules

Question 11

What species are combined to produce carbamoyl phosphate?

A) NH₃, PO₄^3-, HCO₃^-
B) NH₄⁺, PO₄^3-, Ac-CoA, releasing CoA-SH
C) glycine and inorganic phosphate, releasing CO₂
D) acetate and NH₄⁺, releasing CO₂
E) alanine and inorganic phosphate, releasing acetate

Question 12

Which urea cycle intermediate reacts with carbamoyl phosphate?

A) citrulline
B) aspartate
C) argininosuccinate
D) arginine
E) ornithine

Question 13

What enzyme associated with the urea cycle enzyme is activated by N-acetylglutamate?

A) carbamoyl phosphate synthetase
B) glutamate dehydrogenase
C) argininosuccinate synthetase
D) arginase
E) ornithine transcarbamoylase

Question 14

Degradation to pyruvate makes an amino acid _____; degradation to acetoacetate makes an amino acid _____.

A) glucogenic; glucogenic
B) glucogenic; glucogenic and ketogenic
C) glucogenic; ketogenic
D) ketogenic; glucogenic
E) ketogenic; ketogenic

Question 15

Which of the following amino acids is exclusively ketogenic?

A) Leu
B) Val
C) Phe
D) Arg
E) Thr

Question 16

The cofactor ______ is used to transfer C-1 units such as methyl, formyl, and methenyl groups.