Assertion :The evolution of molecular oxygen is concerned with photosystem- I. Reason: Photosystem- II has no role in evolution of oxygen.

Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

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Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.

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Assertion is correct but Reason is incorrect.

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Both Assertion and Reason are incorrect.

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Solution

The correct option is D Both Assertion and Reason are incorrect.
Photosystem II has a P680 reaction center wherein oxygen atoms of two water molecules bind to a cluster of manganese atoms. These Mn atoms are bound to the reaction center and associated with an enzyme that splits water, removes electrons one at a time. These electrons fill the holes which are left in the reaction center due to the release of light-energized electrons. Immediately after the removal of four electrons from the two water molecules, $O_{2}$ is released. The absence of PS II results in cyclic photophosphorylation by PSI that does not have a water-splitting complex and no oxygen is released.
Thus the correct answer is option D.

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Similar questions

Assertion (A) Order and molecularity are same.

Reason (R) Order is determined experimentally and molecularity is the sum of the stoichimetric coeffcient of rate determining elementary step.

(a) Both assertion and reason are correct and the reason is correct explanation of assertion
(b) Both assertion and reason are correct, but reason does not explain assertion.
(c) Assertion is correct, but reason is incorrect
(d) Both assertion and reason are incorrect
(e) Assertion is incorrect but reason is correct.

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