The cytochrome chain collects electrons from NADH and FADH2 and passes them to O2.

Electron transfer is coupled to the pumping of protons across the mitochondrial membrane and the generation of a proton gradient.

Energy stored in the proton gradient is used by ATP synthase to generate ATP.

Electron Transport Chain (ETC)

Complexes I, III, and IV use the energy from electron transport to translocate protons out of the mitochondrial matrix against an electrochemical gradient. The H+ gradient, called the proton motive force, thus formed is then used by ATP synthase to generate ATP.

Electron Carriers:

• Coenzyme Q (Ubiquinone): Transfers electrons from Complex I and II to Complex III.
• Cytochrome c: Transfers electrons from Complex III to Complex IV.

Overall ATP Yield:

• Each NADH yields approximately 2.5 ATP, and each FADH2 yields about 1.5 ATP via oxidative phosphorylation.

Electron transport inhibitors:

The mnemonic is, "CRAP Tightens Muscle AND Produces Muscle ACHe" Ouch!

Complex I (NADH: ubiquinone oxidoreductase) inhibitors mnemonic

C - Chlorpromazine

R - RotenONE (insecticide/pesticide/piscicide)

A - Amobarbital

P - Piercidin A

Complex II (Succinate dehydrogenase) inhibitors mnemonic

Tightens - Thenoyltrifluoroaceteate