Q: Which of the following equations correctly represents the overall reaction of aerobic respiration?

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

Question 1

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

Accepted Answer

To transfer electrons from NADH and FADH$_2$ to oxygen, creating a proton gradient across the membrane

Question 2

During oxidative phosphorylation, which molecule acts as the final electron acceptor in the electron transport chain?

Accepted Answer

O$_2$

Question 3

Which of the following statements about ATP synthase is correct?

Accepted Answer

ATP synthase is embedded in the inner mitochondrial membrane and uses the proton gradient to synthesize ATP from ADP and P$_i$

Question 4

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

Accepted Answer

NADH donates electrons at a higher energy level in the electron transport chain than FADH$_2$

Question 5

A mutation causes a defect in Complex I of the electron transport chain. Which of the following would most likely be observed?

Accepted Answer

Decreased ATP production due to impaired NADH oxidation

Question 6

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

Accepted Answer

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

Question 7

In the context of the electron transport chain, what is the main role of the proton gradient across the inner mitochondrial membrane?

Accepted Answer

To drive the synthesis of ATP by ATP synthase

Question 8

Which of the following best describes chemiosmosis?

Accepted Answer

The movement of protons down their electrochemical gradient through ATP synthase to generate ATP

Question 9

If a cell is exposed to cyanide, which inhibits cytochrome c oxidase (Complex IV), what is the most immediate effect on cellular respiration?

Accepted Answer

Electron transport chain halts, leading to a rapid decrease in ATP production

Question 10

Which of the following is NOT a product of the electron transport chain?

Accepted Answer

CO$_2$

Question 11

A patient is diagnosed with a mitochondrial disorder that impairs the function of ATP synthase. Which of the following would you expect to observe in their cells?

Accepted Answer

A buildup of protons in the intermembrane space

Question 12

Which of the following best explains why the inner mitochondrial membrane is essential for oxidative phosphorylation?

Accepted Answer

It provides a barrier that allows the establishment of a proton gradient necessary for ATP synthesis

Question 13

Which of the following statements about NAD$^+$ and FAD is correct?

Accepted Answer

Both act as electron carriers, accepting electrons during metabolic reactions and donating them to the electron transport chain

Question 14

In a scenario where the proton gradient across the inner mitochondrial membrane is dissipated by an uncoupling agent, what would be the effect on ATP synthesis and oxygen consumption?

Accepted Answer

ATP synthesis decreases while oxygen consumption remains the same or increases

Question 15

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 16

Which of the following is a correct sequence of events in aerobic respiration?

Accepted Answer

Glycolysis $\rightarrow$ Krebs cycle $\rightarrow$ Electron transport chain $\rightarrow$ ATP synthesis

Question 17

A researcher adds a chemical that blocks the transfer of electrons from Complex III to cytochrome c. What is the most likely outcome?

Accepted Answer

Electron flow through the electron transport chain stops, and ATP synthesis decreases

Question 18

Which of the following best explains why oxygen is required for aerobic respiration?

Accepted Answer

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

Question 19

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

Accepted Answer

Pumping of protons from the mitochondrial matrix to the intermembrane space

Question 20

A cell is found to have a defective NADH dehydrogenase (Complex I). Which of the following would be the most direct consequence?

Accepted Answer

Reduced ability to oxidize NADH, leading to decreased proton pumping and ATP synthesis

Bacterial Respiration and Electron Transport Chain: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards