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Question #45289
The Question
Colchicine is frequently used in agricultural genetics to develop superior plant varieties. If a meristematic cell of a diploid plant (2n = 16) is treated with colchicine during active division, which of the following accurately describes the molecular mechanism of its action and the subsequent chromosomal consequence?
Options
- A.
It inhibits the depolymerization of kinetochore microtubules, arresting the cell in anaphase and causing aneuploidy.
- B.
It binds to tubulin dimers to prevent microtubule polymerization, arresting the cell at metaphase and ultimately inducing autopolyploidy.
- C.
It blocks the cleavage of cohesin proteins by separase, preventing centromere splitting and leading to allopolyploidy.
- D.
It specifically disrupts the formation of the phragmoplast during cytokinesis, resulting in a binucleate cell with two diploid nuclei.
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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
Kinetochore|Tubulin|Spindle Fibres|Polyploidy
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Differentiating the exact molecular target of colchicine (tubulin polymerization) from other cell cycle inhibitors, and distinguishing its macroscopic genetic outcome (autopolyploidy) from aneuploidy.
Common Misconception: Students often confuse aneuploidy (failure of a single chromosome pair to separate) with polyploidy (complete failure of the spindle apparatus leading to whole-genome duplication), or they mistakenly assume colchicine only blocks cytokinesis rather than karyokinesis.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell Cycle and Cell Division - Class 11 |
| Concept | Spindle Attachment Geometry |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |