* NADH: Reduced nicotinamide adenine dinucleotide. It is produced during glycolysis and the Krebs cycle.
* FADH2: Reduced flavin adenine dinucleotide. It is produced during the Krebs cycle.
These molecules are considered "electron carriers" because they pick up electrons from other molecules during metabolic reactions and then deliver them to the electron transport chain. This process is essential for the production of ATP, the main energy currency of the cell.
Here's a brief summary of how this works:
1. Electron Carriers: NADH and FADH2 carry high-energy electrons.
2. Electron Transport Chain: These electrons are passed down a series of protein complexes embedded in the inner mitochondrial membrane.
3. Energy Release: As electrons move down the chain, they release energy. This energy is used to pump protons (H+) across the membrane, creating a proton gradient.
4. ATP Production: The proton gradient drives the movement of protons back across the membrane through ATP synthase. This process generates ATP.
So, NADH and FADH2 are the crucial molecules that fuel the electron transport chain and ultimately lead to the production of ATP.
