Oxidative Phosphorylation & ATP Synthesis — NEET Biology

Oxidative phosphorylation couples electron transport with ATP synthesis in the mitochondrial inner membrane. As electrons move through the ETS, their energy is used to pump protons, creating a gradient that drives ATP synthase—not the electrons directly making ATP. Students often confuse this with substrate-level phosphorylation or think electrons themselves form ATP bonds. Remember: O₂ is the final electron acceptor, accepting electrons and H⁺ to form water. The key is that electron energy is trapped in a proton gradient, which then powers ATP synthesis. This energetics concept is fundamental to NEET's focus on cellular respiration efficiency.