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

Question 1

Which of the following statements best describes the main difference between fermentation and aerobic respiration?

Accepted Answer

Aerobic respiration requires oxygen as the final electron acceptor, while fermentation does not.

Question 2

During glycolysis, glucose is converted into two molecules of pyruvate. What is the net gain of ATP and NADH per glucose molecule?

Accepted Answer

$2$ ATP and $2$ NADH

Question 3

Which molecule acts as the final electron acceptor in the electron transport chain during aerobic respiration?

Accepted Answer

Oxygen ($O_2$)

Question 4

In cellular respiration, which process directly produces the most ATP?

Accepted Answer

Oxidative phosphorylation

Question 5

Which of the following is a correct description of a redox reaction in cellular respiration?

Accepted Answer

The molecule that loses electrons is oxidized, and the molecule that gains electrons is reduced.

Question 6

NAD+ is converted to NADH during cellular respiration. What type of reaction is this, and what is the role of NADH?

Accepted Answer

Reduction; NADH carries electrons to the electron transport chain.

Question 7

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

Accepted Answer

$C_6H_{12}O_6 + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{energy}$

Question 8

During the citric acid cycle, how many NADH molecules are produced per turn of the cycle?

Accepted Answer

$3$

Question 9

Which step in cellular respiration is responsible for generating the proton gradient used to power ATP synthase?

Accepted Answer

Electron transport chain

Question 10

If a cell is deprived of oxygen, which process will continue to function, and which will stop?

Accepted Answer

Glycolysis will continue; electron transport chain will stop.

Question 11

Which molecule contains most of the energy from glucose after glycolysis is complete?

Accepted Answer

Pyruvate

Question 12

What is the main function of the electron transport chain in cellular respiration?

Accepted Answer

To transfer electrons from NADH and FADH$_2$ to oxygen, forming water and generating a proton gradient

Question 13

Which of the following best explains why oxygen is considered the ultimate electron acceptor in cellular respiration?

Accepted Answer

Oxygen has a high affinity for electrons and forms water when it accepts electrons.

Question 14

Which two electron carrier molecules feed electrons into the electron transport system?

Accepted Answer

NADH and FADH$_2$

Question 15

Chemiosmosis is a key process in oxidative phosphorylation. What is chemiosmosis?

Accepted Answer

The movement of protons ($H^+$) down their concentration gradient through ATP synthase to generate ATP.

Question 16

Which of the following is true about substrate-level phosphorylation?

Accepted Answer

It involves the direct transfer of a phosphate group from an organic substrate to ADP to form ATP.

Question 17

During the conversion of pyruvate to acetyl CoA, which molecules are produced?

Accepted Answer

NADH and CO$_2$

Question 18

Which of the following steps in cellular respiration does NOT require oxygen?

Accepted Answer

Glycolysis

Question 19

What is the role of the proton-motive force in ATP synthesis?

Accepted Answer

It drives protons ($H^+$) through ATP synthase, resulting in the production of ATP.

Question 20

If a mutation prevents the formation of FADH$_2$ during the citric acid cycle, which of the following would most likely occur?

Accepted Answer

The electron transport chain would receive fewer electrons, resulting in decreased ATP production.

Cellular Respiration and Fermentation: Study Guide

Study Guide - Practice Questions