Question

a. Explain how the ATP synthase uses the H⁺ gradient to generate   ATP.

b. How do the mitochondria establish a higher concentration of H⁺ on one side of the membrane?

c. Where does the H⁺ come from?

Answer 1

Ans.

(a) Each pair of electron transfer from NADH to O2 transfers 10 protons, from matrix ( negative side) to inter membranous space (positive side) .

ATP synthase has two distinct part in their structure-

F1

F0

F1 is a peripheral membrane protein structure and responsible for ATP synthesis, while F0 is a trasmembrane protein made up of several transmembrane protein and responsible for proton flow from IMS (inter membranous space) to matrix.

this F0 particle has proton pore which leaks protons as fast as they are pumped by electron transfer.

this leakage of protons from transmembrane C subunits of F0 causes rotation in C subunits along with gamma subunit, which is associated with beta subunits .

three beta subunits alternatively present with three alpha subunits in F1 paticle.

these beta subunits has ATP synthesis site and synthesize ATP when rotate with the leakage of protons via C subunits.

(b)

When electrons are transferred fron NADH or FADH they generate vectorial proton transfer force fron matrix to IMS.

hence each pair of electron when transferred from reductant to the final acceptor O2 transfers total 10 proton from matrix negative side to IMS(positive side).

(c)

These proton  comes from matrix and NADH+H+.