Chemiosmotic Hypothesis

Generation of ATP in light reaction is called photophosphorylation.

Chemiosmotic hypothesis was first explained by P. Mitchell.

As a result of (a) photolysis towards thylakoid lumen, (b) quinone pump, which takes H+ from stroma to lumen, and (c) NADP+ reductase reaction towards stroma; H+ concentration in thylakoid lumen increases by 1000-2000 times and as a result a proton motive force develops.

This force is responsible for ATP synthesis on the head of CF0 – ­CF1 particle plugged on thylakoid membrane. The CF0 part forms facilitated channel for proton diffusion towards stroma. Movement of 3H+ is involved in the synthesis of 1 ATP.

Related Topic Name

cyclic and non cyclic photophosphorylation and The Electron Transport
Prior knowledge of the photosynthesis and early experiments
where does photosynthesis occur?
Photosynthetic Pigments
Photosynthetic Units / Pigment Systems
Mechanism of Photosynthesis
Non - Cyclic Photophosphorylation
Splitting of water
Where are ATP and NADPH used ?
The C4 Pathway {Hatch and Slack Pathway}
Photorespiration
Factors affecting Photosynthesis