What is the role of NADH and FADH2 in cellular respiration?

NADH and FADH2 play a crucial role in cellular respiration as electron carriers. During the processes of glycolysis and the citric acid cycle, these molecules are produced when glucose and other substrates are oxidized. Their primary function is to transport electrons to the electron transport chain, a series of proteins located in the inner mitochondrial membrane.

Once NADH and FADH2 deliver their electrons to the electron transport chain, the energy released from the electron transfer is used to pump protons (H+ ions) across the mitochondrial membrane, creating a proton gradient. This gradient is essential for ATP synthesis because it drives ATP synthase, leading to the production of ATP. Therefore, the role of NADH and FADH2 as electron carriers is vital for the overall process of converting the energy stored in glucose into a usable form of energy in cells.