NAD+ and FAD are known as _______ because they are _______ during catabolic steps in the breakdown of organic molecules. Question 3 options: A) Substrates, phosphorylated B) Enzymes, catabolizing C) Electron donors, oxidized D) Electron transporters (coenzymes), reduced

• D) Electron transporters (coenzymes), reduced

Explanation:

NAD+ and FAD are oxidizing agents, which can also be called electron acceptors. They accept high-energy electrons and carry them to the electron transport chain for synthesis of ATP molecules. When these electron carriers accept electrons, they get reduced to NADH and FADH2. In the anabolic process, NADH is oxidized back to NAD+, and FADH2 is oxidized back to FAD releasing the stored energy that is used to synthesize the energy currency of the cell (ATP)