Question

What is meant by an electro chemiccal proton gradient which helps in formation of ATP in ETC?

Answer 1

Dear student,
Chemiosmosis requires a semi permeable membrane, proton pump, proton gradient and ATPase. Hydrogen ions diffuse from an area of high proton concentration to an area of lower proton concentration and accumulate in the inter membrane space. The pH of outer surface of inner mitochondrial membrane lowers considerably due to concentration of net positive charge. Thus a pH gradient is generated across the inner mitochondrial membrane. The outward pumping of H⁺ also generates a proton concentration gradient across the membrane. pH gradient and the proton concentration gradient across the inner membrane build a proton electrochemical gradient. The proton motive force drives protons across the membrane towards the mitochondrial matrix. The return flow of proton down their electrochemical gradient through the enzymatic complex is responsible for the activation of ATPase which drives the synthesis of ATP from ADP and phosphate.

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