Before You Begin
Question #45262
The Question
In a rapidly growing Zea mays (C4 plant) seedling, a highly specific chemical inhibitor completely neutralizes RuBisCO activity. How will this metabolic block most likely impact the plant's cellular kinetics and photosynthetic pathway?
Options
- A.
CO2 assimilation halts in the agranal chloroplasts of bundle sheath cells, causing carbon starvation that prolongs the G1 phase of interphase due to a lack of metabolic precursors.
- B.
Primary CO2 fixation by PEPcase in the mesophyll cells ceases immediately, leading to a rapid depletion of ATP and a subsequent arrest of the cell cycle at the G2/M transition.
- C.
The plant shifts to photorespiration in the mesophyll cells to compensate for the block, utilizing excess ATP and NADPH, which shortens the overall duration of interphase.
- D.
RuBisCO inhibition in the granal chloroplasts of bundle sheath cells prevents the regeneration of PEP, causing an accumulation of malate and immediate M-phase arrest.
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
Rubisco Dual Functionality|C4 Pathway Efficiency|Interphase Duration Paradox
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often mistakenly believe that C4 plants do not rely on RuBisCO because PEPcase is the primary acceptor.
This question tests the absolute necessity of the C3 cycle in all plants, the specific location/anatomy of C4 chloroplasts (agranal in bundle sheath), and synthesizes this with cell cycle regulation (G1 checkpoint dependence on metabolic precursors).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell Cycle and Cell Division - Class 11 |
| Concept | Interphase Duration Paradox |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |