ATP SYNTHESIS CHEMOSMOTIC MODEL
P. Mitchell's hypothesis states that ATP synthesis has intimate dependence on the way, in which electrons and protons are transported along the respiratory chain. The hypothesis requires meeting a number of conditions, which are enumerated below.
1. The inner mitochondrial membrane must be intact and impermeable for protons making their way inward from the outside.
2. As the result of the respiratory chain activity, hydrogen ions arrive in it from inside, from the matrix, and break free on the outer side of the membrane.
3. The motion of hydrogen ions, directed outward from inside, results in their accumulation. Owing to this, between two sides of the mitochondrial membrane pH gradient appears.
4. Maintaining of this gradient requires expenditure of energy. This energy is provided by electron transport along the electron-transport chain.
5. ATP synthesis is maintained by electrochemical gradient.