Rucete ✏ Campbell Biology In a Nutshell
Unit 2 THE CELL — Concept 9.4 During Oxidative Phosphorylation, Chemiosmosis Couples Electron Transport to ATP Synthesis
Oxidative phosphorylation is the process by which ATP is synthesized as electrons are transferred from electron donors to oxygen via a series of electron carriers. This process occurs in the mitochondria and is essential for energy production in aerobic organisms.
1. The Electron Transport Chain (ETC)
- Location: Inner mitochondrial membrane.
- Components: A series of protein complexes (I–IV) and associated molecules that facilitate electron transfer.
- Function: Electrons from NADH and FADH₂ move through these complexes, releasing energy used to pump protons into the intermembrane space, creating a proton gradient.
2. Chemiosmosis and ATP Synthesis
- Proton Gradient: The ETC creates a high concentration of protons in the intermembrane space.
- ATP Synthase: Protons flow back into the mitochondrial matrix through this enzyme, powering the phosphorylation of ADP to ATP.
3. Oxygen's Role
- Final Electron Acceptor: Oxygen accepts electrons at the end of the ETC and combines with protons to form water.
In a Nutshell
- Oxidative phosphorylation couples electron transport and chemiosmosis to efficiently produce ATP, the cell's main energy currency.