Question 1

Which of the following statements best describes the difference between anabolic and catabolic pathways in cellular metabolism?

Accepted Answer

Anabolic pathways decrease entropy and require energy input, while catabolic pathways increase entropy and release energy.

Question 2

ATP is often referred to as the 'energy currency' of the cell. What is the standard free energy change ($$\Delta G^\circ') $$for the hydrolysis of ATP to ADP and inorganic phosphate?

Accepted Answer

$$\Delta G^\circ' = -7.3$$ kcal/mol

Question 3

Which molecule acts as a coenzyme in oxidoreductase reactions and is derived from the vitamin niacin?

Accepted Answer

NAD

Question 4

During glycolysis, what is the net gain of ATP and NADH molecules per molecule of glucose metabolized?

Accepted Answer

2 ATP, 2 NADH

Question 5

In the absence of oxygen, what is the primary fate of pyruvate in human muscle cells?

Accepted Answer

It is converted to lactate.

Question 6

Which of the following best explains why brown fat is important for newborn mammals?

Accepted Answer

Brown fat contains thermogenin, which uncouples electron transport from ATP synthesis, generating heat.

Question 7

Which of the following reactions is an example of a reduction reaction?

Accepted Answer

$$\mathrm{CH_3CHO} + [2H] \rightarrow \mathrm{CH_3CH_2OH}$$

Question 8

Which compartment of the mitochondrion is the site of the Krebs cycle?

Accepted Answer

Matrix

Question 9

What is the main role of the electron transport chain in aerobic respiration?

Accepted Answer

To transfer electrons from reduced coenzymes to oxygen, pumping protons to generate a proton gradient

Question 10

Which of the following best describes the Q cycle in the electron transport chain?

Accepted Answer

It allows additional protons to be pumped without additional electrons being transported.

Question 11

If a mammal had the uncoupling protein thermogenin present in all of its mitochondria, what would be the most likely physiological consequence?

Accepted Answer

The animal would generate excessive heat and have difficulty maintaining energy balance.

Question 12

Which of the following is NOT a way cells store chemical energy?

Accepted Answer

Lactate

Question 13

Which process is regulated mostly by allosteric mechanisms in the cell?

Accepted Answer

Glycolysis

Question 14

Which of the following best explains why the hydrolysis of phosphoenolpyruvate (PEP) releases more free energy than the hydrolysis of ATP?

Accepted Answer

PEP has a higher-energy phosphate bond than ATP.

Question 15

Which of the following is a correct balanced equation for ATP hydrolysis?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H_2O} \rightarrow \mathrm{ADP} + \mathrm{P_i} + \mathrm{H^+}$$

Question 16

Which of the following best describes the fate of glucose-1-phosphate produced by phosphorolytic cleavage of glycogen?

Accepted Answer

It is converted to glucose-6-phosphate and enters glycolysis.

Question 17

Which of the following is a direct product of the Krebs cycle for each acetyl-CoA that enters?

Accepted Answer

3 NADH, 1 FADH2, 1 ATP

Question 18

Which of the following best explains why cells accumulate reduced compounds during metabolism?

Accepted Answer

Reduced compounds store energy that can be released during oxidation.

Question 19

Which of the following is a correct description of the role of ATP synthase in mitochondria?

Accepted Answer

It uses the proton gradient to synthesize ATP from ADP and Pi.

Cellular Energy Metabolism: Glycolysis, Fermentation, and Aerobic Respiration

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