(Bio-Forum, 2015)
To sum up what goes on here, all the NADH + H+ and FADH2 that was made in the previous steps of cellular respiration (gylcolysis, pyruvate oxidation and krebs cycle) are now going to be broken down.
Remember that to make these, they had to GAIN electrons and protons. This mean they have a lot of potential (stored) energy.
This potential energy will be used to create ATP as well as water.
HOW IT WORKS
*Recall: To have a high electronegativity means to be more attractive to electrons*
We got some complexes that play hot potatoe with one another. They pass on the electrons that NADH+H+ and FADH2 give to them. The order they go in is important: from low electronegativity to high electronegativity. Oxygen has the highest electronegativity, meaning electrons find oxygen the most attractive.
1. NADH+H+ gives it's electrons and protons (therefore being oxidized) to Complex I (therefore being reduced).
2. Complex I passes the electrons onto Complex II and so on, creating a relay of oxidizing and reducing.
3. FADH2 is a bit lazy and only starts at UQ, meaning it makes less ATP.
4. Now the protons travel through proton pumps into the intermembrane space, which has a high proton concentration.
5. The protons in here go through Chemiosmosis: making ATP with all the protons combined with the enzyme ATP synthase
*since this is making ATP with ENERGY it's OXIDATIVE PHOSPHORYLATION
6. Now, since electrons find oxygen so attractive, they keep going through each complex until they reach oxygen. Oxygen is what keeps the ETC moving, if it wasn't so attractive then no electrons would want to move and the ETC would clog up!
7. Oxygen makes some water