$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} \rightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + \text{Energy}$$

Question 1

Which of the following best describes the role of oxygen in cellular respiration?

Accepted Answer

Oxygen acts as the final electron acceptor in the electron transport chain, forming water.

Question 2

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

Accepted Answer

$$2$$ ATP and $$2$$ NADH

Question 3

Which of the following equations correctly represents the overall process of aerobic cellular respiration?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} ightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + 	ext{Energy}$$

Question 4

Which enzyme is responsible for catalyzing the conversion of pyruvate to acetyl CoA, and what are the products of this reaction?

Accepted Answer

Pyruvate dehydrogenase; products are acetyl CoA, NADH, and $$\mathrm{CO_2$}$$

Question 5

In the citric acid cycle, how many NADH molecules are produced per turn of the cycle, and how many turns occur per glucose molecule?

Accepted Answer

3 NADH per turn; 2 turns per glucose

Question 6

Which of the following statements about redox reactions in cellular respiration is correct?

Accepted Answer

Glucose is oxidized to carbon dioxide, and oxygen is reduced to water.

Question 7

What is the main purpose of the electron transport chain in mitochondria?

Accepted Answer

To create a proton gradient that drives ATP synthesis via chemiosmosis

Question 8

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

Accepted Answer

Oxidative phosphorylation

Question 9

During lactic acid fermentation, which molecule acts as the final electron acceptor?

Accepted Answer

Pyruvate

Question 10

Which of the following best explains why fats yield more ATP per gram than carbohydrates during cellular respiration?

Accepted Answer

Fats have more C-H bonds, which are highly reduced and can donate more electrons to the electron transport chain.

Question 11

Which of the following is a similarity between fermentation and aerobic respiration?

Accepted Answer

Both use glycolysis to oxidize glucose and produce ATP.

Question 12

If a poison blocks the function of ATP synthase, which of the following would you expect to happen?

Accepted Answer

The proton gradient would remain but ATP production would stop.

Question 13

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

The direct transfer of a phosphate group from a substrate to ADP to form ATP.

Question 14

In alcohol fermentation, what is the fate of pyruvate?

Accepted Answer

It is converted to ethanol and $$\mathrm{CO_2$}.$$

Question 15

Which of the following is a correct sequence of energy flow during cellular respiration?

Accepted Answer

Glucose $$\rightarrow$$ NADH $$\rightarrow$$ Electron Transport Chain $$\rightarrow$$ Proton Motive Force $$\rightarrow$$ ATP

Question 16

Which of the following statements about the citric acid cycle is FALSE?

Accepted Answer

It directly produces most of the cell’s ATP.

Question 17

Which molecule is both an electron carrier and an oxidizing agent during cellular respiration?

Accepted Answer

NAD$$^+$$

Question 18

A patient’s muscle cells are deprived of oxygen. Which process will allow them to continue producing ATP?

Accepted Answer

Lactic acid fermentation

Question 19

Which of the following best explains why NAD$$^+$$ regeneration is essential for glycolysis to continue under anaerobic conditions?

Accepted Answer

NAD$$^+ is $$required to accept electrons during the oxidation of glyceraldehyde-3-phosphate.

Cellular Respiration and Fermentation: Mechanisms of Energy Harvest in Cells

Study Guide - Practice Questions