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Question #45208
The Question
A C3 plant is maintained exactly at its light compensation point under controlled conditions. It relies on precise carbohydrate partitioning and osmotic regulation to survive this low-light stress. Which of the following statements regarding its metabolic and osmotic state is INCORRECT?
Options
- A.
At the light compensation point, the rate of CO2 fixation by RuBisCO exactly matches the rate of CO2 evolution from cellular respiration and photorespiration.
- B.
Starch is the preferred storage polysaccharide because it is osmotically inert; its accumulation does not significantly lower the water potential of the chloroplast.
- C.
If the plant stored its energy reserves as reducing monosaccharides instead of starch, the cellular solute potential (Ψs) would become less negative, causing an efflux of water.
- D.
The mobilization of stored starch for phloem loading involves converting it into sucrose, which is an osmotically active but chemically non-reducing transport sugar.
Check Your Answer
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
Reducing vs Non-reducing Sugars|Compensation Point Logic|C3 Cycle Stoichiometry
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot & Word-Play Trap: This question tests the inverse relationship between solute concentration and solute potential (Ψs).
Students frequently harbor the misconception that adding solutes makes the potential 'higher' or 'less negative'.
By combining this osmotic principle with the biochemical nature of starch vs. reducing sugars, the question forces the student to synthesize concepts from 'Transport in Plants', 'Photosynthesis', and 'Biomolecules'.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biomolecules - Class 11 |
| Concept | Reducing vs Non-reducing Sugars |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |