What is the reaction catalyzed by complex III in the electron transport system? A) UQH₂ + O₂ UQ + H₂O B) UQH₂ + complex IV⁺ UQ + complex IV C) FADH₂ + UQ FAD + UQH₂ D) UQH₂ + cytochrome c⁺ UQ + cytochrome c

Question

Quizplus · Accepted Answer

Complex III (also known as cytochrome bc1 complex) catalyzes the transfer of electrons from ubiquinol (UQH2) to cytochrome c. Therefore, the correct reaction catalyzed by complex III is UQH2 + 2 cytochrome c (Fe3+) + 2 H+ ⟶ UQ + 2 cytochrome c (Fe2+) + 4 H+. Choice D is the only option that includes UQH2 (in the form of UQH₂) and cytochrome c as reactants, and UQ and cytochrome c as products.

What Is the Reaction Catalyzed by Complex III in the Electron