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Question:

Read the following four statements, A, B, C, and D and select the right option having both correct statements.
Statement (A) Z scheme of light reaction takes place in presence of PS-I only.
(B) Only PS-I is functional in cyclic photophosphorylation.
(C) Cyclic photophosphorylation results into synthesis of ATP and NADPH2.
(D) Stroma lamellae lack PS-II as well as NADP.

C and D

B and C

B and D

A and B

Solution:

Z scheme of light reaction is noncyclic flow of an electron from PSII through quinone, cytb6f complex and plastocyanin to NADPH via PSI; it includes both PSI and PSII. In cyclic photophosphorylation, electrons are passed from P700 of PS-I via electron transfer chain to back to P700 with the formation of ATP. It does not include PS II. Electrons are not passed to NADP reductase; no NADPH2 is formed. Stroma lamellae lack PS II as well as NADP reductase enzyme while grana lamellae have both PS I and PS II. Thus, the correct answer is option B.