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Oxidative Phosphorylation

In this IBDP Biology topic, you can learn the process of oxidative phosphorylation.
- Oxidative Phosphorylation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing energy which is used to reform ATP.
- Oxidative phosphorylation involved two processes the electron transport chain and chemiosmosis.
Process
- Energy carried by electrons from reduced coenzymes which are produced by the Krebs cycle (1 reduced FAD, 3 reduced NAD)
- Hydrogen atoms are released from the products of the Krebs cycle which are reduced NAD and FAD. They are then oxidized to NAD and FAD. The hydrogen atom splits into a proton and electron.
- The electrons move down the electron transport chain releasing energy at each carrier. This energy is then used to pump protons from the mitochondrial matrix into the inter-membrane space.
- The concentration of protons is now higher in the intermembrane space than in the mitochondrial matrix – forms electrochemical gradient.

- Protons move down the electrochemical gradient back into the mitochondrial matrix by ATP synthaseThe movement of hydrogen ions across a membrane which generates ATP is called chemiosmosis.
The movement of hydrogen ions across a membrane which generates ATP is called chemiosmosis.
In the mitochondrial matrix, at the end of the electron transport chain the protons, electrons and oxygen combine to form water – oxygen is said to be the final electron accepter.
This is the end of the topic

Drafted by Eva (Biology)
Photo references:
- https://byjus.com/biology/oxidative-phosphorylation/
- https://en.wikipedia.org/wiki/Cellular_respiration