Oxidative Phosphorylation
1. The hydrogen ions flow from the inter-membrane space back into the mitochondrial matrix through Complex V, also called ATP synthase. The energy lost by hydrogen ions in ATP synthase is coupled to the synthesis of ATP. This is sometimes referred to as the chemi-osmotic process.
2. Electrons from NADH lost substantial amounts of energy in Complexes I, III and IV. Those from FADH2 had less energy to lose, and did so in Complexes III and IV. This fact will be important in explaining the different energy yields from carbohydrates and fats.
3. The entire process requires an uninterrupted supply of oxygen. Without oxygen to be the point of disposal of the used electrons, electron transport stops and no more ATP is made.
4. The Second Law of Thermodynamics dictates that no process can be perfectly efficient. This one is no different. Some of the energy lost as heat is used to maintain our body temperature.
