Question 1

Which of the following best explains why ATP hydrolysis is highly exergonic under cellular conditions?

Accepted Answer

ATP hydrolysis results in the formation of products with greater resonance stabilization, reduced electrostatic repulsion, increased entropy, and better hydration compared to ATP.

Question 2

Which of the following statements about the coupling of metabolic reactions is correct?

Accepted Answer

A thermodynamically unfavorable reaction can proceed if it is coupled to a reaction with a sufficiently negative $$\Delta G.$$

Question 3

In the context of intermediary metabolism, which of the following best describes the role of catabolic pathways?

Accepted Answer

They break down complex molecules into simpler ones, releasing chemical energy.

Question 4

Which compound has the highest phosphoryl-transfer potential based on the provided $$\Delta G$$ values?

Accepted Answer

Phosphoenolpyruvate

Question 5

Why are fats a more efficient energy source than carbohydrates?

Accepted Answer

Fats are more reduced, so their oxidation yields more reducing equivalents and thus more ATP.

Question 6

Which of the following best describes the function of the citric acid cycle in aerobic metabolism?

Accepted Answer

It oxidizes acetyl-CoA to CO$$_2$$, generating NADH and FADH$$_2$$ for ATP production.

Question 7

Which of the following is a key regulatory mechanism for controlling metabolic flux through a pathway?

Accepted Answer

Allosteric regulation of enzymes catalyzing irreversible steps.

Question 8

During glycolysis, which reaction is directly coupled to the generation of ATP via substrate-level phosphorylation?

Accepted Answer

The conversion of phosphoenolpyruvate to pyruvate.

Question 9

Which of the following best explains why the hydrolysis of ATP to ADP and $$P_i is $$used to drive endergonic reactions in cells?

Accepted Answer

The hydrolysis of ATP has a large negative $$\Delta G$$, which can be coupled to reactions with positive $$\Delta G to $$make the overall process favorable.

Question 10

Which of the following is NOT a reason for the high phosphoryl-transfer potential of ATP?

Accepted Answer

ATP hydrolysis results in a decrease in entropy.

Question 11

A metabolic pathway is considered amphibolic if it:

Accepted Answer

Functions both anabolically and catabolically depending on cellular needs.

Question 12

Which of the following best describes the role of NADH and FADH$$_2 in $$cellular metabolism?

Accepted Answer

They act as electron carriers, transferring electrons to the electron transport chain for ATP production.

Question 13

Which of the following statements about the regulation of glycolysis is correct?

Accepted Answer

ATP allosterically inhibits phosphofructokinase-1 (PFK-1), providing feedback inhibition.

Question 14

Which of the following best describes the energy charge of a cell?

Accepted Answer

A measure of the relative concentrations of ATP, ADP, and AMP that regulates metabolic pathways.

Question 15

Which of the following is a real-life example of a high-energy phosphate compound used to regenerate ATP during intense muscle activity?

Accepted Answer

Creatine phosphate

Question 16

Which of the following is true regarding the oxidation of glyceraldehyde 3-phosphate in glycolysis?

Accepted Answer

The oxidation is coupled to the formation of 1,3-bisphosphoglycerate, a compound with high phosphoryl-transfer potential.

Question 17

Which of the following best describes the role of compartmentalization in metabolic regulation?

Accepted Answer

It allows opposing metabolic pathways to occur in different cellular locations, preventing futile cycles.

Question 18

Which of the following statements about the ATP/ADP cycle is correct?

Accepted Answer

It is the fundamental mode of energy exchange in biological systems, constantly recycling ATP to provide energy.

Question 19

Which of the following is a direct consequence of the hydrolysis of ATP to ADP and $$P_i$$?

Accepted Answer

An increase in entropy due to the production of two molecules from one.

Question 20

Which of the following best describes the function of the light-harvesting complex in photosynthesis?

Accepted Answer

It captures light energy and transfers it to the reaction center to drive electron transport.

Metabolism Basics: Chemical Logic and Bioenergetics

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