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 molecule combines with acetyl CoA to form citric acid?

Accepted Answer

Oxaloacetate

Question 3

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

Accepted Answer

$$2$$

Question 4

Which coenzyme is reduced to FADH2 during the citric acid cycle, and at which step does this occur?

Accepted Answer

FAD; during the conversion of succinate to fumarate

Question 5

What is the final electron acceptor in the electron transport system, and what is formed as a result?

Accepted Answer

Oxygen; water

Question 6

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

Accepted Answer

Electron transport system (oxidative phosphorylation)

Question 7

If a poison blocks the function of ATP synthase, what immediate effect would this have on the cell?

Accepted Answer

The cell would be unable to generate ATP via oxidative phosphorylation

Question 8

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

Accepted Answer

$$2 \mathrm{H}^+ + 2 \mathrm{e}^- + \frac{1}{2} \mathrm{O}_2 \rightarrow \mathrm{H}_2\mathrm{O}$$

Question 9

Which of the following statements about fat metabolism is correct?

Accepted Answer

Fatty acids are broken down into acetyl groups, which enter 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 in the cytoplasm

Question 11

Which of the following best explains why muscle cramping occurs during intense exercise?

Accepted Answer

Lactic acid accumulates due to anaerobic metabolism of glucose

Question 12

How many molecules of NADH are produced from one molecule of glucose by the end of the citric acid cycle (including all previous steps)?

Accepted Answer

$$10$$

Question 13

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

Accepted Answer

CO2

Question 14

What is the net gain of ATP from the complete aerobic catabolism of one molecule of glucose in a human cell?

Accepted Answer

$$36$$

Question 15

Which of the following best describes the role of NAD+ in cellular respiration?

Accepted Answer

It carries high-energy electrons from metabolic pathways to the electron transport system

Question 16

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

Accepted Answer

Protein catabolism

Question 17

Which of the following steps in cellular respiration does NOT occur in the mitochondria?

Accepted Answer

Glycolysis

Question 18

Which of the following best explains why the electron transport system requires oxygen?

Accepted Answer

Oxygen acts as the final electron acceptor, allowing the chain to continue

Question 19

If a cell is deprived of oxygen, which of the following will occur first?

Accepted Answer

The electron transport system will stop

Question 20

Which of the following is a correct summary equation for the ATP synthesis catalyzed by ATP synthase?

Accepted Answer

$$\mathrm{ADP} + \mathrm{P}_i \rightarrow \mathrm{ATP}$$

Cellular Respiration: Citric Acid Cycle & Electron Transport System

Study Guide - Practice Questions