Final answer:
The NAD+ and FAD are coenzymes necessary for oxidation-reduction reactions catalyzed by oxidoreductase apoenzymes, which are crucial for ATP production in cells.
Step-by-step explanation:
Oxidoreductase Apoenzymes and Their Coenzymes
Oxidoreductas apoenzymes are crucial for catalyzing oxidation-reduction reactions, where they facilitate the transfer of electrons through the removal of hydrogen atoms from substrates. These enzymes require coenzymes to function properly, with NAD+ (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide) being two of the most common coenzymes involved in these reactions. These coenzymes carry high-energy electrons and protons, which are essential for the production of ATP, the energy currency of the cell.
When NAD+ accepts electrons and protons, it becomes NADH, while FAD becomes FADH2 when it undergoes a similar reduction. These reduced forms are energy-rich molecules that contribute to the electron transport chain, which ultimately leads to the generation of ATP. Understanding the role of NAD+ and FAD as coenzymes is fundamental in biochemistry, particularly in energy metabolism.