Question 1

Which of the following best describes the primary function of the electron transport chain (ETC) in aerobic cellular respiration?

Accepted Answer

To create a proton gradient across the inner mitochondrial membrane by transferring electrons through a series of redox reactions

Question 2

During the citric acid cycle, which molecule acts as a competitive inhibitor to regulate the cycle when energy supplies are high?

Accepted Answer

NADH

Question 3

What is the net ATP yield from glycolysis per molecule of glucose under aerobic conditions?

Accepted Answer

2 ATP

Question 4

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

Accepted Answer

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

Question 5

If a mutation caused Complex I of the electron transport chain to become nonfunctional, which of the following would be the most immediate effect?

Accepted Answer

NADH would be unable to donate electrons to the chain, reducing ATP production

Question 6

Which step in aerobic respiration produces the most NADH per glucose molecule?

Accepted Answer

Citric acid cycle

Question 7

A patient is diagnosed with a genetic disorder that impairs the function of ATP synthase. Which process would be most directly affected?

Accepted Answer

Oxidative phosphorylation in the mitochondria

Question 8

Which of the following best explains why the citric acid cycle slows down when ATP and NADH levels are high?

Accepted Answer

High ATP and NADH act as allosteric inhibitors, decreasing the activity of key enzymes in the cycle

Question 9

During aerobic respiration, which process is responsible for the majority of ATP production?

Accepted Answer

Electron transport chain and oxidative phosphorylation

Question 10

If a cell is deprived of oxygen, which of the following steps in cellular respiration would be directly inhibited?

Accepted Answer

Electron transport chain

Question 11

Which of the following statements about the energy yield from glucose oxidation is correct?

Accepted Answer

The complete oxidation of one glucose molecule releases approximately $-685$ kcal of energy

Question 12

Which molecule is the final electron acceptor in the electron transport chain of aerobic respiration?

Accepted Answer

O$_2$

Question 13

A researcher adds a chemical that dissipates the proton gradient across the inner mitochondrial membrane. What is the most likely outcome?

Accepted Answer

ATP synthesis by ATP synthase will decrease

Question 14

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

ATP is produced directly by the transfer of a phosphate group from a substrate to ADP

Question 15

In the context of cellular respiration, what is the main purpose of redox reactions in the electron transport chain?

Accepted Answer

To transfer electrons to oxygen and pump protons to create a gradient

Question 16

Which of the following is a direct product of the citric acid cycle per turn (per acetyl-CoA)?

Accepted Answer

2 NADH, 1 FADH$_2$, 1 ATP (or GTP), 2 CO$_2$

Question 17

A poison that blocks the transfer of electrons from Complex III to Complex IV in the electron transport chain would result in which of the following?

Accepted Answer

A buildup of reduced electron carriers before Complex IV

Question 18

Which of the following best explains why NADH yields more ATP than FADH$_2$ during oxidative phosphorylation?

Accepted Answer

NADH donates electrons to Complex I, which pumps more protons than Complex II where FADH$_2$ donates electrons

Question 19

If a cell is running low on NAD$^+$, which process in cellular respiration would be most directly affected?

Accepted Answer

Glycolysis

Aerobic Cellular Respiration: Pathways, Regulation, and Electron Transport

Study Guide - Practice Questions