Peter D. Mitchell has proposed the hypothesis chemiosmotic in 1961. The chemiosmotic theory essentially suggests that most of ATP synthesis in cells respiring comes from the electrochemical gradient between the interior membranes of mitochondria using the energy of NADH and FADH2 formed by the degradation of energy-rich molecules such as glucose. Molecules such as glucose are metabolized to produce acetyl-CoA as an energy-rich intermediary.
The oxidation of acetyl-CoA in the mitochondrial matrix is associated with the reduction of a carrier molecule such as NAD and FAD. Carriers of electrons pass to the transport chain mail (ETC) in the mitochondrial inner membrane, which in turn transmit them to other proteins in the ETC. The available energy in the electrons is used to pump protons from the matrix in the mitochondrial inner membrane, the storage of energy in the form of an electrochemical gradient transmembrane. The return on the market of protons through the inner membrane by the enzyme ATP synthase. The flow of protons in the matrix of mitochondria by the ATP synthase provides enough energy to ADP to combine with inorganic phosphate to form ATP. The electrons and protons at the last pump in the ETC are supported by oxygen to form water.
It is a radical proposal at the time, and has not been well accepted. The prevailing view is that the energy of electron transfer was stored in a high potential intermediaries stable, chemically a more conservative. The problem with the old paradigm is no intermediate high energy has never been found, and evidence for pumping protons by the complex chain of electron transfer grew too large for be ignored. Finally, the weight of evidence has begun to promote chemiosmotic hypothesis and, in 1978, Peter Mitchell received the Nobel Prize in Chemistry. Chemiosmotic coupling is important for the production of ATP in chloroplasts and many bacteria.