Question

Explain the chemiosmotic mechanism of ATP generation. How does oxidative phosphorylation compare with substrate level phosphorylation found in glycolysis and th e Kreb’s cycle?

Answer 1

The theory behind the chemiosmotic mechanism is that if electrons gets transferred along electron transport system through a number of oxidation and reduction reactions releases energy. This energy allows the chain to transport hydrogen ions through the membrane and create a electrochemical potential difference.

This charge separation of electro motive force provide energy required for enzymes like ATP synthase which is used to catalize the synthesis of ATP from ADP. This is takes place when protons move along the membrane energy released makes the rotor and stalk of ATP synthase to rotate. Thus mechanical energy is converted to chemical energy as phosphate is added is added to ADP to form ATP.

In both oxidative phosphorylation and substrate level phosphorylation there is a adding of phosphate group to ADP to form ATP. In substrate level phosphorylation direct phosphorylation of ADP with a phosphate group and the energy provided from a coupled reaction. In oxidative phosphorylation ATP is produced by the oxidation of NADH and FADH₂ which inturn does the electron transfer and pumping of protons generating a electrochemical gradient which provide power for ATP synthase.