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.

1. Energy carried by electrons from reduced coenzymes which are produced by the Krebs cycle (1 reduced FAD, 3 reduced NAD)
2. 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.
3. 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.
4. The concentration of protons is now higher in the intermembrane space than in the mitochondrial matrix – forms electrochemical gradient.

1. 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.

2. The movement of hydrogen ions across a membrane which generates ATP is called chemiosmosis.

3. 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

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Drafted by Eva (Biology)

Photo references:

1. https://byjus.com/biology/oxidative-phosphorylation/
2. https://en.wikipedia.org/wiki/Cellular_respiration