1) Hydrogen atoms are released as reduced NAD and reduced FAD are oxidised to NAD and FAD. Hydrogen is then split into H+ and e-.
2) The electrons move along the electron transport chain, made up of three electron carriers, losing energy at each carrier.
3) This energy is used to pump protons from the mitochondrial matrix into the intermembrane space. The concentration of protons is now higher in the intermembrane space, so an electrochemical gradient is formed.
4) Protons move down this gradient, back to the matrix, via ATP synthase. This movement drives the synthesis of ATP from ADP and Pi. This movement is called chemiosmosis.
6) In the matrix, at the end of the transport chain, the protons, electrons, and O2 (from the blood) combine to form water. O2 is the final electron acceptor.