AP BIOLOGY

Detailed explanation-1: -Oxidative phosphorylation produces 24–28 ATP molecules from the Kreb’s cycle from one molecule of glucose converted into pyruvate.

Detailed explanation-2: -ATP molecules maximally generated from one molecule of glucose = 686/12 = 57 ATP molecules.

Detailed explanation-3: -Electrons from NADH and FADH2 are then transferred to molecular oxygen, coupled to the formation of an additional 32 to 34 ATP molecules by oxidative phosphorylation.

Detailed explanation-4: -Oxygen is a vital constituent of this process for its role as the final electron acceptor. Therefore, oxidative phosphorylation cannot take place in absence of oxygen. Hence, the correct answer is (D).