Final answer:
The immediate source of energy for oxidative phosphorylation is the high-energy electron carriers NADH and FADH₂. These carriers are utilized in the mitochondria to generate ATP through a series of reactions involving electron transfer and proton pumping.
Step-by-step explanation:
The proximate (immediate) source of energy for oxidative phosphorylation is neither glucose directly nor ATP; rather, it is the high-energy electron carriers NADH and FADH₂, which are produced during various stages of glucose catabolism. Specifically, the answer to your question is C) NADH and D) FADH₂. These molecules donate electrons through a series of reactions that power proton pumps and ultimately lead to the production of ATP in the mitochondria, a process that is fundamental to cellular metabolism.
Regarding another aspect of cellular respiration, during the catabolism of glucose, FADH₂ is produced only in the Krebs cycle, which is part of the pathway that generates ATP molecules. Oxidative phosphorylation is the process that uses NADH and FADH₂ to generate ATP, and it involves the transfer of electrons to oxygen, which then combines with hydrogen ions to form water.