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Which of the following would NOT occur in a chloroplast in which PS II has been blocked but PS I is working normally?

(a) transfer of electrons from PS I to its acceptor Your answer
(b) release of O₂ Correct
(c) excitation of P₇₀₀ Your answer
(d) cyclic ATP formation Your answer

Your answer: Correct answer: (b)

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Explanation

Why (b) is correct

With PS II blocked, water is not split, so no O₂ is released. PS I can still be excited and run cyclic ATP formation.

Why the other options are wrong

(a) · your answer PS I still passes electrons to its acceptor.
(c) · your answer P700 is still excited by light.
(d) · your answer Cyclic flow uses PS I only, so it continues.

NCERT point: O₂ release depends on PS II.

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