Question: Photosynthesis is a redox reaction. explain.

Dear student 

Yes it is redox reaction. Photosynthesis involves the reduction of carbon dioxide into sugars and the oxidation of water into molecular oxygen. The reverse reaction, respiration, oxidizes sugars to produce carbon dioxide and water.

Photosynthesis is a redox process where oxidation and reduction both occurs.

CO2 + H2O → (CH2O) +O2

Oxidation

During photosynthesis, water gets oxidized to oxygen (O2).

2H2O →O2 + 4 [H.] Requires light energy

Reduction

4 [H.] + CO2 →(CH2O) +H2O

In photosynthesis, CO2 gets reduced to carbohydrates. Using the ATP and NADPH produced by the light-dependent reactions, the resulting compounds are then reduced and removed to form further carbohydrates, like glucose.

The balance between the NADP/NADPH determines the redox state. Each redox reaction has an oxidation half and a reduction half.

NADP+ getting reduced to NADPH is the reduction half and water giving rise to oxygen is the oxidation half.

Hope it helps