What role do NADH and FADH2 play in cellular respiration?

NADH and FADH2 play a crucial role in cellular respiration as key electron carriers. During the processes of glycolysis and the citric acid cycle, electrons are removed from substrates and transferred to these molecules. When NAD+ and FAD accept electrons, they are reduced to NADH and FADH2, respectively.

These reduced forms then transport the high-energy electrons to the electron transport chain, which is embedded in the inner mitochondrial membrane. As the electrons pass through the chain, their energy is used to pump protons across the membrane, creating a proton gradient. This gradient is essential for ATP production, as it drives the synthesis of ATP via ATP synthase. Thus, NADH and FADH2 are integral to the overall energy production in cellular respiration, facilitating the conversion of energy stored in nutrients into a usable form of chemical energy in ATP.