Question

In oxidative phosphorylation, inhibition of complex III would most directly lead to accumulation of which of the following?

• A. NAD+
• B. NADH
• C. Reduced Ubiquinol (QH2)
• D. Cytochrome c in oxidized form

Hint:

Focus on understanding the electron transport chain complexes and how their inhibition affects the flow of electrons and accumulation of intermediates.

Answer 1

The Correct Option is C

Inhibition of complex III in the electron transport chain would cause the accumulation of reduced ubiquinol (QH2) because electrons cannot be passed from ubiquinol to cytochrome c. NADH would accumulate as well due to a backup of the electron flow, but QH2 directly accumulates as a result of complex III inhibition.