Question

Explain chemiosmotic hypothesis for ATP synthesis.

Answer 1

The chemiosmotic hypothesis was proposed by Peter Mitchell. The ATP and NADH${}_2$ generated during the light reaction is used for carbon dioxide fixation during the dark reaction.
According to the chemiosmotic hypothesis, ATP is produced by due to the proton gradient created across the mitochondrial membrane. The essential components required for chemiosmosis are proton pump, proton gradient and ATP synthase. ATP synthase is an enzyme which helps in ATP synthesis. The enzyme ATP synthase has two part $F_0$ and $F_1$. $F_0$ is the part which transports protons across the membrane as a transmembrane channel while configuration changes in $F_1$ activates the enzyme. They phosphorylate ADP i.e., add one more phosphorus group to the ADP and converts ADP(adenosine diphosphate) to ATP (adenosine triphosphate). The proton gradient developed across the membrane is the driving force of ATP synthase.