Peter Mitchell’s chemiosmotic theory proposed “chemiosmotic hypothesis in 1961. The theory suggests essentially that most ATP synthesis in cellular respiration, is an electrochemical gradient between the inner membrane and intermembrane space of the mitochondria, using the energy of NADH and FADH2 that have been formed by the breakdown of energy-rich molecules such as glucose. Molecules such as glucose, are metabolized to produce acetyl-CoA as an intermediate rich in energy. oxidation of acetyl-CoA in the mitochondrial matrix is coupled to the reduction of a carrier molecule such as NAD and FAD. The carriers pass electrons to the electron transport chain in the inner mitochondrial membrane, which then transferred to other proteins in transport chain.The available energy in the electrons is used to pump protons from the matrix across the inner mitochondrial membrane, saving energy in the form of a transmembrane electrochemical gradient. The protons are returned through the inner membrane by the enzyme ATP synthase. The flow of protons back into the mitochondrial matrix via ATP synthase provides enough energy for ADP to combine with inorganic phosphorus to form ATP. The electrons and protons in the last pump protein transport chain are taken to Oxygen (O2) to form water (H2O). This was a radical proposal at the time, and was not well accepted. The prevailing view was that the energy of electron transfer was stored is an intermediate high-energy stable, a more conservative view of the chemical.The problem with this old paradigm was that this agent was never found, and evidence of proton pumping by the complexes of the electron transport chain grew in such a way that could not be ignored. Eventually the weight of evidence began to favor the chemiosmotic hypothesis, and in 1978, the Nobel Prize in chemistry was awarded to Peter Mitchell. The chemiosmotic coupling is important in the production of ATP in the chloroplast and many types of bacteria.
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