Oxygen Accepts Electrons to Sustain the Electron Transport Chain and ATP Production
- The electron transport chain (ETC) transfers electrons through a series of protein complexes.
- As electrons move through the chain, they must be continuously removed at the end to keep the process flowing.
- Without a final electron acceptor, electrons would accumulate and the chain would stop.
- Oxygen serves as the terminal electron acceptor, accepting electrons from the final carrier in the ETC.
- A common misconception is that oxygen is directly involved in ATP synthesis.
- In reality, oxygen’s role is to accept electrons, enabling the electron transport chain to function and sustain the proton gradient needed for ATP production.
How Oxygen Accepts Electrons and Forms Water
- Oxygen accepts electrons from the final complex in the ETC.
- Simultaneously, oxygen combines with protons (H⁺) from the mitochondrial matrix.
- This removes both electrons and protons from the system, preventing their accumulation.
- This reaction produces metabolic water (H₂O):
$$\text{O}_2 + 4\text{e}^- + 4\text{H}^+ \rightarrow 2\text{H}_2\text{O}$$
