Question 1

Which of the following best describes the primary function of the citric acid cycle in cellular respiration?

Accepted Answer

To generate high-energy electron carriers (NADH and FADH2) for use in the electron transport system

Question 2

During the citric acid cycle, what is the fate of the carbons from the original acetyl group?

Accepted Answer

They are released as $$CO_2$$

Question 3

Which coenzyme is reduced when succinate is converted to fumarate in the citric acid cycle?

Accepted Answer

FAD

Question 4

How many molecules of ATP are produced directly by substrate-level phosphorylation during the citric acid cycle per glucose molecule?

Accepted Answer

$$2$$

Question 5

What is the final electron acceptor in the electron transport system?

Accepted Answer

Oxygen ($$O_2)$$

Question 6

Which process is responsible for the majority of ATP production during cellular respiration?

Accepted Answer

Electron transport system and oxidative phosphorylation

Question 7

If a poison blocks the function of ATP synthase, which of the following would be the most immediate effect?

Accepted Answer

ATP production by oxidative phosphorylation would stop

Question 8

Which of the following equations correctly represents the formation of water at the end of the electron transport system?

Accepted Answer

$$\frac{1}{2}O_2$ + 2H^+ + 2e^- \rightarrow H_2O$$

Question 9

Which of the following best explains why fats yield more ATP than carbohydrates when metabolized?

Accepted Answer

Fatty acids are longer and produce more acetyl CoA units for the citric acid cycle

Question 10

During anaerobic respiration in humans, what is the fate of pyruvate?

Accepted Answer

It is converted into lactic acid

Question 11

Which of the following is a waste product of the citric acid cycle?

Accepted Answer

$$CO_2$$

Question 12

What is the net gain of ATP molecules from the complete aerobic catabolism of one glucose molecule, accounting for the cost of shuttling NADH into the mitochondria?

Accepted Answer

$$36$$

Question 13

Which of the following statements about protein catabolism is correct?

Accepted Answer

Amino acids are deaminated, and the remaining carbon backbone enters the citric acid cycle

Question 14

Which step in cellular respiration is responsible for the majority of $$CO_2$$ production?

Accepted Answer

Preparatory step and citric acid cycle

Question 15

Which of the following best describes oxidative phosphorylation?

Accepted Answer

The production of ATP using energy derived from the redox reactions of the electron transport chain

Question 16

If a cell is deprived of oxygen, which of the following processes will be directly inhibited?

Accepted Answer

Electron transport system

Question 17

Which of the following is NOT a product of the electron transport system?

Accepted Answer

NADH

Question 18

Which of the following best explains why lactic acid builds up in muscles during intense exercise?

Accepted Answer

Oxygen supply is insufficient, causing pyruvate to be converted to lactic acid

Question 19

Which of the following correctly matches the molecule with its role in cellular respiration?

Accepted Answer

NADH: Delivers high-energy electrons to the electron transport system

Question 20

A patient is experiencing muscle wasting due to starvation. Which metabolic process is most likely increased in this scenario?

Accepted Answer

Protein catabolism

Cellular Respiration: Citric Acid Cycle & Electron Transport System

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