Which coenzyme is known as a hydrogen carrier in cellular respiration?

Flavin adenine dinucleotide (FAD) plays a crucial role as a hydrogen carrier in cellular respiration. During the process of oxidative phosphorylation, FAD is involved in redox reactions, acting as an electron acceptor. It is reduced to FADH2 when it accepts hydrogen atoms (which include protons and electrons) during the Krebs cycle.

FADH2 subsequently donates these electrons to the electron transport chain, where they are used to help generate ATP through oxidative phosphorylation. This capacity to carry hydrogen atoms allows FAD to influence the energy yield of cellular respiration, as it contributes to the production of energy-rich molecules like ATP.

While NADH also functions as a hydrogen carrier, the question specifically asks for a choice that was identified as FAD. Coenzyme A primarily serves to shuttle acetyl groups in metabolic processes rather than acting as a direct hydrogen carrier. ATP, while critical in energy transfer, is not a carrier of hydrogen but rather a molecule that stores and transfers energy within cells.