During oxidative phosphorylation, which compound serves as the final electron acceptor?

During oxidative phosphorylation, oxygen (O2) acts as the final electron acceptor in the electron transport chain. This process occurs in the inner mitochondrial membrane, where electrons are transferred through a series of protein complexes, ultimately leading to the conversion of energy stored in reduced cofactors like NADH and FADH2 into ATP.

As the electrons travel down the chain, they release energy that is used to pump protons (H+) from the mitochondrial matrix into the intermembrane space, creating an electrochemical gradient. This proton gradient then drives ATP synthesis when protons flow back into the matrix through ATP synthase.

At the end of the electron transport chain, the electrons combine with molecular oxygen and protons to form water. This step is crucial, as it maintains the flow of electrons through the chain; without oxygen to accept the electrons, the entire process would halt, leading to a backup of the electron transport chain and a cessation of ATP production.

Ultimately, the role of oxygen as the final electron acceptor is vital for the efficient production of ATP during aerobic respiration. This distinguishes it clearly from NAD+ and FADH2, which serve as electron carriers earlier in the metabolic pathways, or ATP, which is the product of the process rather than