Question

Read the assertion and reason carefully to mark the correct option in question.

Assertion: The whole scheme of transfer of electrons, starting from the $PSII$ uphill to the acceptor, down the electron transport chain to $PSI$, excitation of electrons, transfer to another acceptor, and finally downhill to $NAD{P}^{+}$ causing it to be reduced to $NADPH+H^{+}$ is called the $Z$ scheme or cyclic photo-phosphorylation.

Reason: Both $ATP$ and $NADH+H^{+}$ are synthesised by this kind of electron flow.

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

Answer 1

The correct option is D If both assertion and reason are false

Assertion-Reason relation

$Z$ scheme is the representation of the oxidation and reduction changes that occur in the light reaction during photosynthesis. This scheme represents the transfer of electrons from $PSII$ to $PSI$. This transfer of electrons between photosystems is a non-cyclic process and hence, it is also referred to as non-cyclic photo-phosphorylation. Hence, the assertion statement is false.

Assertion-Reason relation

The main significance of non-cyclic photo-phosphorylation is the production of energy molecules, $ATP$ and $NADPH$, which are further used in the production of glucose in plants. Hence, the reason statement is false.

Final answer

(D) If both assertion and reason are false.