What is the source of electrons for the electron transport chain that follows the Citric Acid Cycle?

The source of electrons for the electron transport chain following the Citric Acid Cycle is primarily the NADH and FADH2 that are generated during the cycle. As the citric acid cycle proceeds, various reactions occur that facilitate the oxidation of acetyl-CoA, leading to the reduction of NAD+ to NADH and FAD to FADH2. These reduced cofactors—NADH and FADH2—carry high-energy electrons that are crucial for the electron transport chain.

Once inside the mitochondria, NADH and FADH2 donate their electrons to the electron transport chain, initiating a series of redox reactions that ultimately result in the production of ATP through oxidative phosphorylation. This process not only utilizes the high-energy electrons but also contributes to the proton gradient across the mitochondrial membrane, which is essential for ATP synthesis by ATP synthase.

In contrast, GTP produced in the cycle serves as an energy currency but does not directly contribute electrons for the electron transport chain. ATP produced in glycolysis, while important for energy transfer within the cell, is not a direct source of electrons for the chain. Acetyl-CoA, although vital for entering the citric acid cycle, is not involved in electron transport as it gets converted