Question

Assertion: Protons or hydrogen ions produced by photolysis of water accumulate in the lumen of thylakoids.
Reason: Photolysis of water takes place in inner membrane of thylakoid.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (B)

The first step in photosynthesis is the light-driven oxidation (splitting or photolysis) of water. It provides the electrons for the photosynthetic electron transport chains as well as protons for the establishment of a proton gradient. It occurs on the lumenal side of the thylakoid membrane. During photolysis, water is oxidised to oxygen, protons and electrons. Protons accumulate in the lumen.