Role of NAD in oxidative phosphorylation

1. Organic molecules are oxidised during glycolysis, link reaction and Krebs cycle, producing high energy electrons and protons. 
2. NAD serves as a mobile proton and electron carrier, carrying these electrons and protons to the electron transport chain on cristae of mitochondria.  
3. High energy electrons in NADH reduce electron acceptors of ETC; NAD is re-oxidised. 
4. Electrons passing down the ETC is coupled to production of ATP. Protons liberated in the oxidation of NADH establish the proton motive force. Reoxidation of NADH allows regeneration of coenzyme NAD⁺ so they can pick up more electrons and protons from Krebs cycle etc. so that these reactions can continue.
5. 1 reduced NAD to 3 ATP through oxidative phosphorylation.