In cellular respiration, FADH2 is formed when FAD accepts how many hydrogen atoms?

FADH2 is formed when FAD (flavin adenine dinucleotide) accepts two hydrogen atoms during the process of cellular respiration, specifically in the Krebs cycle. When a molecule of FAD is reduced, it accepts two hydrogen ions and two electrons, which transforms it into FADH2. This reduced form of FAD plays a crucial role in the electron transport chain, where it contributes to the production of ATP, the energy currency of the cell. The acceptance of two hydrogens is vital as it allows the molecule to carry the high-energy electrons to the mitochondrial inner membrane for further energy extraction through oxidative phosphorylation.