Question 1

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

Accepted Answer

O$$_2$$

Question 2

What is the primary function of Complex IV (cytochrome c oxidase) in the electron transport chain?

Accepted Answer

To transfer electrons from cytochrome c to O$$_2$$

Question 3

During aerobic respiration, which of the following best describes the role of NADH and FADH$$_2$$?

Accepted Answer

They donate electrons to the electron transport chain

Question 4

If a mutation prevents cytochrome c from functioning, what is the most likely consequence for the cell?

Accepted Answer

Electrons will not be transferred from Complex III to Complex IV

Question 5

Which equation correctly represents the formation of water at the end of the electron transport chain?

Accepted Answer

$$\mathrm{O_2$} + 4\mathrm{e^-} + 4\mathrm{H^+} \rightarrow 2\mathrm{H_2O}$$

Question 6

What is the main purpose of the proton gradient established by the electron transport chain?

Accepted Answer

To drive the synthesis of ATP via ATP synthase

Question 7

Which of the following best explains how ATP synthase produces ATP?

Accepted Answer

By allowing protons to flow down their gradient, causing a conformational change that catalyzes ATP formation

Question 8

A patient has a genetic defect that impairs the function of Complex I in the electron transport chain. Which molecule's oxidation would be most directly affected?

Accepted Answer

NADH

Question 9

If the inner mitochondrial membrane becomes permeable to protons, what will happen to ATP production?

Accepted Answer

ATP production will decrease because the proton gradient is dissipated

Question 10

Which of the following is the correct sequence of electron flow in the electron transport chain?

Accepted Answer

NADH → Complex I → Coenzyme Q → Complex III → Cytochrome c → Complex IV → O$$_2$$

Question 11

Which of the following best describes the role of Coenzyme Q (ubiquinone) in the electron transport chain?

Accepted Answer

It transfers electrons between Complex I/II and Complex III

Question 12

A toxin blocks the transfer of electrons from Complex III to cytochrome c. What is the most immediate effect?

Accepted Answer

Proton pumping at Complex IV will stop

Question 13

How many ATP molecules are produced directly by the passage of three protons through ATP synthase?

Accepted Answer

1

Question 14

Which of the following statements about the electron transport chain is TRUE?

Accepted Answer

The energy released during electron transfer is used to pump protons across the inner mitochondrial membrane

Question 15

In a scenario where oxygen is not available, what happens to the electron transport chain?

Accepted Answer

It stops because there is no final electron acceptor

Question 16

Which of the following best explains why FADH$$_2$$ yields less ATP than NADH when oxidized in the electron transport chain?

Accepted Answer

FADH$$_2$$ donates electrons at Complex II, bypassing Complex I and resulting in fewer protons pumped

Question 17

A researcher adds a chemical that specifically inhibits ATP synthase. What is the most likely result?

Accepted Answer

The proton gradient will increase, but ATP production will decrease

Question 18

Which of the following is a direct result of electrons moving through the electron transport chain?

Accepted Answer

Protons are pumped from the mitochondrial matrix to the intermembrane space

Question 19

Which of the following best describes the relationship between the electron transport chain and oxidative phosphorylation?

Accepted Answer

The electron transport chain creates a proton gradient that drives ATP synthesis via oxidative phosphorylation

Question 20

A patient is exposed to cyanide, which inhibits Complex IV. What is the most likely effect on cellular respiration?

Accepted Answer

Electron flow through the chain will stop, and ATP production will decrease sharply

Aerobic Respiration and the Electron Transport Chain: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards