8 oxidative phosphorylation

where does oxidative phosphorylation occur?

the mitochondrial inner membrane (cristae)

what’s mostly made in this stage?

most of the ATP

what 3 things are involved in this stage?

• the ETC

• movement of protons across the inner mitochondrial membrane

• catalysed by ATP synthase

what happens during oxidative phosphorylation? (stages 1-3)

1. hydrogen atoms are donated by NADH and FADH from the Krebs cycle

2. hydrogen atoms split into protons (H⁺ions) and electrons

3. the electrons enter the ETC; energy is released as they pass between electron carriers

• The electron transport chain is made up of electron carrier proteins that are embedded in the inner mitochondrial membrane

what happens during oxidative phosphorylation? (stages 4-5)

4. the released energy is used to actively transport protons across the inner mitochondrial membrane from the matrix into the intermembrane space

5. the protons move down their concentration gradient back to the matrix by facilitated diffusion; they move via proton channels that are associated with ATP synthase

   • This movement of protons is known as chemiosmosis

what happens during oxidative phosphorylation? (6)

6. ATP synthase catalyses the formation of ATP from ADP and Pi

• At the end of the electron transport chain the electrons pass to oxygen, which acts as the final electron acceptor

  • oxygen combine with protons and electrons at the end of the electron transport chain to form water as a waste product