Question

Photolysis of water is involved in

• A. filling electron gap in PS II
• B. filling electron gap in PS I
• C. creating electrochemical proton gradient
• D. both a and c

Answer 1

The correct option is D both a and c

Splitting of $H_{2}O$:- It occurs in the membrane of the thylakoids. When the chloroplasts (chlorophyll pigment containing plastids) are illuminated with light, 2 molecules of $H_{2}O$ are split into 4$H^{+}$, 4$e^{-}$ and 1 $O_2$is released. These electrons are used to replenish the electrons lost from PS II. The protons released are accumulated in the lumen thus creating an electrochemical proton gradient.
The reaction is as follows
$2H_{2}O\underset{\mathrm{chlorophyll}}{\overset{\mathrm{sunlight}}{\to }}4H^{+}+4e^{-}+O_2$