Deck 24: The Organic Chemistry of the Metabolic Pathways

Question 1

The phosphoanhydride bonds of ATP are termed "high-energy bonds." What does "high-energy bond" mean in this context?

A) A great deal of energy is needed to break a phosphoanhydride bond.
B) Reaction of ATP with a nucleophile has a large, negative ?G°? (an exothermic reaction).
C) Phosphoanhydride bonds have high energy.
D) Reaction of ATP with a nucleophile is uphill thermodynamically.
E) ATP is relatively unreactive.

Answer 1

Reaction of ATP with a nucleophile has a large, negative ?G°? (an exothermic reaction).

Question 2

What is the third stage of catabolism?

A) oxidative phosphorylation
B) the citric acid cycle
C) Gluconeogenesis
D) Fats, carbohydrates, and proteins are hydrolyzed to fatty acids, monosaccharides, and amino acids.
E) Fatty acids, monosaccharides, and amino acids are converted into compounds that enter the citric acid cycle.

Answer 2

the citric acid cycle

Question 3

How many acetyl-CoA's are produced upon catabolism of myristic acid (a C₁₄ fatty acid)?

A) 6
B) 7
C) 8
D) 12
E) 14

Answer 3

7

Question 4

How many FADH₂s are produced upon beta-oxidation of myristic acid?

A) 6
B) 7
C) 8
D) 12
E) 14

Question 5

What enzyme is required for the conversion of 3-phosphoglycerate to 2-phosphoglycerate?

A) a kinase
B) a mutase
C) a transferase
D) a hydroxylase
E) a synthetase

Question 6

How many molecules of CO₂ are produced from myristic acid by catabolism?

A) 6
B) 7
C) 8
D) 12
E) 14

Question 7

Which of the following enzymes is not part of the citric acid cycle?

A) citrate synthetase
B) aconitase
C) phosphoglycerate mutase
D) succinyl-CoA-synthetase
E) fumarase

Question 8

Which of the following compounds can enter the citric acid cycle
Directly?

A) pyruvate
B) lactate
C) acetyl-CoA
D) 2-phosphoglycerate
E) glycerol-3-phosphate

Question 9

How many ATPs are ultimately produced by catabolism and oxidative phosphorylation of myristic acid?

A) 7
B) 14
C) 28
D) 70
E) 94

Question 10

Which of the following statements is true about gluconeogenesis?

A) It is just the reverse of glycolysis.
B) It is responsible for the synthesis of glucose from pyruvate.
C) It uses different enzymes for the irreversible steps of glycolysis (steps 1, 3, and 10).
D) Phosphoenolpyruvate is synthesized in two steps from pyruvate (oxaloacetate is the intermediate).
E) B, C, and D are true.

Question 11

Which of the following amino acids is not an essential amino acid?

A) tyrosine
B) histidine
C) leucine
D) phenylalanine
E) tryptophan