AIIMS 2018 Botany Photorespiration MCQ Question
Assertion: Photorespiration decreases photosynthetic output.
Reason: In photorespiratory pathway, neither ATP nor NADPH is produced.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Correct Answer
Detailed Explanation
Option A is correct because it accurately describes the role of RuBisCo in photorespiration, where it acts as an oxygenase, leading to the fixation of O₂ instead of CO₂, resulting in a 25% loss of fixed CO₂ and energy consumption. This process counteracts the benefits of photosynthesis by utilizing ATP and NADPH without producing energy or reducing power. Other options likely misrepresent the mechanisms of photorespiration or fail to highlight the energy costs associated with this process, which are crucial for understanding its impact on plant efficiency.
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