Question 16.1
2H2O→4H++O2+4e−
Based on the above equation, answer the following questions
(a) Where does this reaction take place in plants?
(b) What is the significance of this reaction?
(a) The reaction takes place in reaction centre PS II, located on the inner surface of thylakoid membrane. It is known as water splitting centre where electrons are extracted from water. The Mn+ and Cl− ions catalyse this reaction.
(b) Splitting of water is an important event in photosynthesis as
(i) It releases molecular oxygen as by product of photosynthesis and is the significant source of oxygen in air, or is essential for all living beings on earth.
(ii) Hydrogen ions produced, are utilised in reducing NADP to NADPH, a strong reducing agent.
(iii) The electrons relased are transferred from PS II to PS I through a series of electron carriers thus, creating a gradient for the synthesis of ATP.