1. NADH carries high-energy electrons: NADH is a reduced form of nicotinamide adenine dinucleotide, meaning it carries two high-energy electrons.
2. Electron transport chain: NADH delivers these electrons to the electron transport chain (ETC), a series of protein complexes embedded in the inner mitochondrial membrane.
3. Electron movement and proton pumping: As the electrons move through the ETC, they lose energy in a stepwise manner. This energy is used to pump protons (H+) across the inner mitochondrial membrane, creating a proton gradient.
4. ATP synthesis: The proton gradient represents potential energy. This energy is harnessed by ATP synthase, an enzyme that uses the flow of protons back across the membrane to synthesize ATP, the primary energy currency of cells.
In summary: NADH acts as an electron carrier, transferring its high-energy electrons to the ETC. This process is coupled to proton pumping, which creates a proton gradient that drives ATP synthesis.
Important note: NADH itself doesn't directly transfer energy to ATP synthesis. It is the movement of electrons through the ETC and the subsequent proton pumping that ultimately leads to ATP production.
