Question

In photosynthesis, splitting of water takes place during

• A. cyclic photophosphorylation
• B. oxidative phosphorylation
• C. non-cyclic photophosphorylation
• D. Calvin cycle

Answer 1

Answer: (C)

Photosynthesis is the process of food preparation by green plants in presence of light. It includes light and dark reactions. Light reaction of photosynthesis involves cyclic and non-cyclic photophosphorylation. In cyclic photophosphorylation electrons released from $P_{700}$ move through a number of acceptors and are then cycled back to $P_{700}$. In non-cyclic photophosphorylation electrons are not cycled back to $P_{680}.$ As a result of this $P_{680}$ becomes oxidised. Electrons are required for the reduction of this oxidised $P_{680}$. The electrons are supplied by water, when it splits into $H^{+}$ and $O_2$ under the influence of light. This is called as splitting or photolysis of water.