Which of the Following is a Two-Electron Donor

Question

Which of the following is a two-electron donor? A) FAD B) Fe−S C) NADH D) NAD⁺ E) cyt c

Accepted Answer

NADH is a two-electron donor because it can donate two electrons and a proton to another molecule, becoming oxidized to NAD+. FAD and Fe-S are also electron donors, but they donate only one electron at a time. Cyt c is a one-electron donor. NAD⁺ is not a known molecule.