What is the role of NADH in cellular respiration?

NADH plays a crucial role in cellular respiration by acting as an electron carrier. During the processes of glycolysis and the Krebs cycle, NAD+ is reduced to NADH when it accepts electrons (and protons), effectively storing energy in the form of high-energy electrons. These NADH molecules then transport the electrons to the electron transport chain, which is located in the inner mitochondrial membrane.

Once in the electron transport chain, NADH donates its electrons, which flow through a series of proteins, ultimately leading to the production of ATP through oxidative phosphorylation. This transfer of electrons is pivotal because it creates a proton gradient across the membrane, driving the synthesis of ATP by ATP synthase. Thus, the primary role of NADH in cellular respiration is to carry electrons to the electron transport chain, where they can be used to produce ATP, the energy currency of the cell.