Question

Which of the following ultimately provides the O₂ used during the process of oxidative phosphorylation?

a) Glucose
b) Water
c) Carbon dioxide
d) Nitrogen

Answer 1

The oxygen used in oxidative phosphorylation is ultimately derived from water, as electrons from glucose catabolism reduce oxygen molecules to ions which combine with hydrogen ions to form water. Correct option is b)

Step-by-step explanation:

The O₂ used during oxidative phosphorylation is ultimately provided by water (b). In the process of oxidative phosphorylation, which occurs in the mitochondria of eukaryotic cells or the plasma membrane of prokaryotic cells, the electrons removed from hydrogen atoms within a glucose molecule during glucose catabolism are eventually used to reduce oxygen molecules to oxygen ions. The oxygen ions, enriched with extra electrons, attract hydrogen ions from the surrounding environment, which results in the formation of water.