Summary
ATP synthesis driven by electron transport and the proton gradient across the inner membrane.
In depth
Most ATP of respiration (around 26 to 28 of about 30) comes from here. Oxidation of NADH is coupled to ATP synthesis via the proton gradient (Mitchell's chemiosmotic hypothesis, Nobel 1978).
This step makes the majority of ATP. It depends on an intact inner membrane and oxygen.
Common mistake: oxygen does not directly make ATP; it acts as final electron acceptor to keep the chain running.
Oxidative phosphorylation is the final stage of respiration, in which ATP is made by using energy from electron transport. The ETC creates a proton gradient, and protons flow back through ATP synthase, driving phosphorylation of ADP to ATP.
It makes about 26 to 28 of the roughly 30 to 32 ATP from a glucose. The process depends on an intact inner membrane; uncouplers like DNP allow protons to leak, making heat but little ATP. Oxygen is needed, so the process stops when it is absent and NADH builds up.
Example: the P/O ratio, about 2.5 ATP per NADH and 1.5 per FADH2, measures coupling efficiency.
Frequently asked questions
What is Oxidative Phosphorylation?
ATP synthesis driven by electron transport and the proton gradient across the inner membrane.
Which area of biology covers Oxidative Phosphorylation, and how advanced is it?
Oxidative Phosphorylation is one of the 53 topics in Metabolism & Bioenergetics. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Cellular Respiration, Electron Transport Chain, Mitochondrial Uncoupling.
Why does Oxidative Phosphorylation matter?
It supplies most of the energy for aerobic cells.
Can you give an example of Oxidative Phosphorylation?
Oligomycin blocks ATP synthase.
What should I learn before Oxidative Phosphorylation?
Work through the Beginner topics in Metabolism & Bioenergetics first, such as Metabolism, Anabolism and Catabolism, ATP, then return to Oxidative Phosphorylation. Intermediate topics assume the Beginner vocabulary.
What topics are related to Oxidative Phosphorylation?
The closest topics to Oxidative Phosphorylation are Cellular Respiration, Electron Transport Chain, Mitochondrial Uncoupling, Light Reactions and ATP Synthesis. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Oxidative Phosphorylation?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Oxidative Phosphorylation. To practise the whole of Metabolism & Bioenergetics, use the Metabolism & Bioenergetics quiz.
How is Oxidative Phosphorylation different from Cellular Respiration?
Oxidative Phosphorylation: ATP synthesis driven by electron transport and the proton gradient across the inner membrane. Cellular Respiration: The process of releasing energy from glucose to make ATP, using oxygen in the aerobic form. Read both side by side and note what each one explains.
What is a common mistake about Oxidative Phosphorylation?
Oxygen does not directly make ATP; it acts as final electron acceptor to keep the chain running.
How should I study Oxidative Phosphorylation step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Cellular Respiration and explain the difference aloud. Finally, take the Metabolism & Bioenergetics quiz and come back to this page for any question you miss.