Question

Photolysis of water occurs in the presence of which element?

• A. Magnesium
• B. Manganese
• C. Calcium
• D. Potassium

Hint:

Manganese is crucial for the functioning of the oxygen-evolving complex in photosystem II, enabling the photolysis of water to occur and generating oxygen as a byproduct.

Answer 1

The Correct Option is B

The photolysis of water, also known as the light-dependent reactions of photosynthesis, involves the splitting of water molecules to release oxygen. This process occurs in the presence of the enzyme water splitting complex within photosystem II. The element manganese (Mn) plays a crucial role in the catalytic activity of this complex, facilitating the oxidation of water molecules into oxygen, protons, and electrons. The manganese ion alternates between different oxidation states, which is essential for this process. The general reaction for water photolysis is: \[ 2H_2O \rightarrow O_2 + 4H^+ + 4e^- \] Thus, manganese (Mn) is the key element involved in the photolysis of water during photosynthesis. Therefore, the correct answer is (b) Manganese.