The electron transport chain drives ATP synthesis using a proton gradient.
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Oxidative phosphorylation is the final stage of aerobic respiration, in which NADH and FADH2 donate electrons to the electron transport chain embedded in the inner mitochondrial membrane. As electrons pass through complexes I, III and IV, protons are pumped into the intermembrane space, creating an electrochemical gradient. ATP synthase lets protons flow back into the matrix and uses that energy to phosphorylate ADP, as described by Peter Mitchell's chemiosmotic theory. Oxygen is the terminal electron acceptor and is reduced to water. Together this stage yields roughly 26 to 28 ATP per glucose.
Key ideas: NADH and FADH2 give electrons to the electron transport chain in the inner mitochondrial membrane, pumping H+ out to build a proton gradient. Protons flow back through ATP synthase, driving ATP formation (chemiosmosis, Mitchell). Oxygen is final electron acceptor, forming water. Roughly 2.5 ATP per NADH and 1.5 per FADH2; total about 30 to 32 ATP per glucose.
Common mistakes and connections: Mistake: thinking ATP is made directly by electron transfer. Uncouplers such as DNP dissipate the gradient, releasing heat instead of ATP. Cyanide blocks complex IV. Old textbooks say 36 to 38 ATP, based on 3 and 2. Links to redox potentials and photosynthesis (similar mechanism).
Approximate ATP per glucose by stage. Oxidative phosphorylation, driven by the proton gradient, contributes the large majority. The interactive lesson shows this as a live animation or chart.
Cyanide binds complex IV and blocks oxygen reduction, which halts ATP production.
The electron transport chain drives ATP synthesis using a proton gradient.
Oxidative Phosphorylation is a advanced topic in Biochemistry, Environment & Industry. It builds on beginner and intermediate topics, so review those first if needed.
Study these earlier topics in Biochemistry, Environment & Industry first: ATP, Glycolysis, Krebs Cycle.
The next topics in Biochemistry, Environment & Industry are Photosynthesis and Light Reactions.
Yes. The interactive lesson includes a self-check question on Oxidative Phosphorylation, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.
Oxidative Phosphorylation is topic 35 of 127 in Biochemistry, Environment & Industry.
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