Final answer:
The correct statement regarding NAD+ is that it accepts two hydrogen atoms when being reduced from NAD+ to NADH, making it an essential electron carrier in cellular metabolism.
Step-by-step explanation:
The correct statement regarding NAD+ is that NAD+ accepts two hydrogen atoms when going from its oxidized to its reduced form. NAD+ is a coenzyme that plays a central role in the energy metabolism of cells, functioning as an electron carrier. During a redox reaction, NAD+ can be reduced to NADH by accepting one hydrogen ion (proton) and two electrons, which corresponds to adding a hydride (H- or a hydrogen atom along with an extra electron) to its structure.
This transformation is crucial in biological systems for the transfer of energy in the form of high-energy electrons. Moreover, the redox reactions involving NAD+ occur at the nicotinamide group, not the adenosine group. The capability of NAD+ to cycle between oxidized (NAD+) and reduced (NADH) forms makes it an efficient molecule in energy extraction processes during cellular respiration and other metabolic pathways.