In oxidative phosphorylation, which enzyme catalyzes the formation of ATP from ADP and inorganic phosphate (Pi) using the proton-motive force across the inner mitochondrial membrane?

• A. NADH dehydrogenase (Complex I)
• B. ATP synthase (Complex V; $F_0{F}_1$-ATPase)
• C. Cytochrome c oxidase (Complex IV)
• D. Succinate dehydrogenase (Complex II)

Answer: (B)

Verified step by step guidance

1. Understand the process of oxidative phosphorylation, which involves the electron transport chain creating a proton gradient across the inner mitochondrial membrane.
2. Recognize that the proton-motive force generated by this gradient is used to drive ATP synthesis from ADP and inorganic phosphate (Pi).
3. Identify the enzyme responsible for harnessing this proton gradient to catalyze ATP formation, which is known as ATP synthase.
4. Recall that ATP synthase is also called Complex V and consists of two main parts: the membrane-embedded F\_0 portion and the catalytic F\_1 portion.
5. Conclude that ATP synthase (Complex V; F\_0F\_1-ATPase) is the enzyme that catalyzes the formation of ATP using the proton-motive force.