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Question #46251
The Question
Consider a C3 angiosperm that typically invests heavily in producing large, zygomorphic flowers for specialized pollinators. When subjected to chronic high temperatures and high light intensity, the plant shifts its reproductive strategy to produce predominantly small, cleistogamous flowers. Which of the following statements regarding the metabolic basis of this phenotypic shift is INCORRECT?
Options
- A.
The competitive binding of O2 to RuBisCO initiates a pathway that consumes ATP and releases CO2 without synthesizing sugars.
- B.
The shift to cleistogamy acts as an energy-conserving morphological trade-off due to the reduced photosynthetic efficiency.
- C.
The plant mitigates this carbon loss by upregulating PEP carboxylase in its mesophyll cells to sustain the energy required for zygomorphy.
- D.
The oxygenation of RuBP yields one molecule of phosphoglycerate and one molecule of phosphoglycolate, initiating a carbon-draining pathway.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Rubisco Dual Functionality|Flower Symmetry|Energy Allocation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between morphological adaptations to stress (cleistogamy) and evolutionary metabolic pathways (C4 pathway).
Students often know PEP carboxylase prevents photorespiration but fail to recognize that a C3 plant cannot spontaneously activate a C4 mechanism to save its carbon budget; it must instead rely on phenotypic plasticity, such as altering floral symmetry and sexuality to conserve energy.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Morphology of Flowering Plants - Class 11 |
| Concept | Flower Symmetry and Sexuality |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |