NEETBotanyPhotosynthesis in Higher Plants
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): During photophosphorylation, protons accumulate in the lumen of the thylakoid rather than the stroma. Reason (R): The primary acceptor of electrons transfers its electron to an H carrier, removing a proton from the stroma and releasing it into the lumen. In the light of the above statements, choose
Options
- ABoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- B(A) is correct but (R) is not correct
- C(A) is not correct but (R) is correct
- DBoth (A) and (R) are correct and (R) is the correct explanation of (A)
Correct answer
D. Both (A) and (R) are correct and (R) is the correct explanation of (A)
Step-by-step solution
During the light reaction, protons are transported across the thylakoid membrane into the lumen. This happens because the primary electron acceptor, located towards the outer side of the membrane, transfers its electron to an H carrier (plastoquinone) rather than directly to an electron carrier. While doing so, it removes a proton from the stroma. When the H carrier passes the electron to the next electron carrier on the inner side of the membrane, the proton is released into the lumen. This mechanism, along with t