What is the primary purpose of oxidative phosphorylation?

The primary purpose of oxidative phosphorylation is to produce ATP using the energy derived from the electron transport chain. During this process, electrons from NADH and FADH2, which are produced in earlier stages of cellular respiration, are transferred through a series of electron carrier proteins located in the inner mitochondrial membrane. As these electrons move through the chain, energy is released and used to pump protons (H+) from the mitochondrial matrix into the intermembrane space, creating a proton gradient.

This buildup of protons creates a potential energy difference across the membrane, often referred to as the proton motive force. ATP synthase, an enzyme located within the inner membrane, harnesses this gradient by allowing protons to flow back into the matrix. The flow of protons through ATP synthase drives the conversion of ADP and inorganic phosphate into ATP. This mechanism is essential for the efficient production of ATP during cellular respiration, making C the correct choice.

In contrast, the other options highlight processes not central to oxidative phosphorylation: generating carbon dioxide is more closely associated with the citric acid cycle; substrate-level phosphorylation specifically refers to the direct production of ATP in glycolysis and the citric acid cycle without the involvement of the electron transport chain; and while NAD+ regeneration