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Question #46287
The Question
In an experiment, an actively dividing plant root apical meristem is treated with colchicine. Assuming sister chromatids manage to separate, the cells still fail to divide their cytoplasm, resulting in a multinucleate (polyploid) condition. Which of the following best explains the exact mechanical failure causing this?
Options
- A.
Inhibition of the Golgi apparatus, preventing the synthesis and packaging of calcium pectate precursors.
- B.
Disruption of the microtubule-based phragmoplast, preventing the alignment of Golgi-derived vesicles at the equator.
- C.
Depolymerization of actin microfilaments, preventing the contraction of the cleavage furrow.
- D.
Failure of chromosomal disjunction during anaphase, leading to unequal distribution of genetic material.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Meristematic Polarity|Golgi Polarity|Microtubule Dynamic Instability
Why This Question Is Tricky
Common Mistakes
The Conceptual Pivot lies in connecting the cytoskeletal target of colchicine (microtubules) to the endomembrane system's role in plant cytokinesis.
Students often memorize that colchicine causes polyploidy via metaphase arrest, but fail to realize that microtubule disruption also directly abolishes phragmoplast formation, preventing Golgi vesicles from building the cell plate.
Distractor C traps students who confuse plant and animal cytokinesis mechanisms.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Anatomy of Flowering Plants - Class 11 |
| Concept | Meristematic Polarity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |