Which molecule acts as an electron carrier during cellular respiration?

NADH is a crucial molecule in cellular respiration that functions as an electron carrier. During the metabolic processes of glycolysis and the Krebs cycle, electrons are transferred to NAD+ to form NADH. This transformation allows NADH to hold onto the high-energy electrons that are released during the breakdown of glucose and other organic molecules.

Once formed, NADH carries these electrons to the electron transport chain, a series of proteins located in the inner mitochondrial membrane. In this chain, NADH donates the electrons, which are then passed through several complexes, ultimately resulting in the production of ATP through oxidative phosphorylation. Therefore, NADH plays a critical role in both the transfer of energy through electrons and the generation of ATP, making it an essential component of cellular respiration.

In contrast, glucose serves as a fuel source rather than an electron carrier, while oxygen, although vital for the final electron acceptor role in cellular respiration, is not responsible for carrying electrons itself. ATP, on the other hand, is the energy currency of the cell, storing and transferring energy but not acting as an electron carrier.