DAT Biology: Cellular Metabolism 4

Question 1

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

Accepted Answer

Oxygen

Answer

Molecular oxygen accepts electrons at Complex IV and is reduced to water.

Question 2

The proton gradient driving ATP synthase is established across which membrane?

Accepted Answer

Inner mitochondrial membrane

Answer

Protons are pumped into the intermembrane space across the inner membrane, creating the proton-motive force.

Question 3

Approximately how many ATP are produced per NADH via oxidative phosphorylation (modern estimate)?

Accepted Answer

2.5

Answer

Each NADH yields about 2.5 ATP, while FADH2 yields about 1.5 ATP.

Question 4

Which mechanism does ATP synthase use to generate ATP?

Accepted Answer

Chemiosmosis

Answer

ATP synthase uses the chemiosmotic flow of protons down their gradient to phosphorylate ADP.

Question 5

Cyanide blocks cellular respiration primarily by inhibiting which complex?

Accepted Answer

Complex IV (cytochrome c oxidase)

Answer

Cyanide binds cytochrome c oxidase, preventing the transfer of electrons to oxygen.

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