In which movement of electrons is energy released to yield an ATP?

Explanation

Energy is released to yield ATP mainly during the transfer of electrons from NADH to coenzyme Q in the electron transport chain. This step occurs at Complex I, where electrons move from NADH to coenzyme Q, releasing enough energy to pump protons across the inner mitochondrial membrane. The resulting proton gradient is later used by ATP synthase to produce ATP. Although electron transfers between cytochrome b and cytochrome c, cytochrome c and cytochrome a, and finally from cytochrome a to oxygen also release energy, these steps primarily help maintain the proton gradient rather than directly generating ATP. Therefore, the movement of electrons from NADH to coenzyme Q is the key step linked to ATP formation.