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Question #45840
The Question
A diploid pollen mother cell (2n = 14) is treated with colchicine prior to meiosis. How does the chromosomal anomaly induced by this treatment fundamentally differ from a stochastic non-disjunction event occurring during Anaphase I?
Options
- A.
Colchicine degrades the centromere causing aneuploidy (n-1, n+1), whereas stochastic non-disjunction causes polyploidy (2n).
- B.
Colchicine inhibits tubulin polymerization leading to a complete set duplication (polyploid gametes, 2n=14), whereas stochastic non-disjunction of a single bivalent produces aneuploid gametes (n=8 and n=6).
- C.
Colchicine prevents homologous recombination leading to diploid gametes, whereas stochastic non-disjunction prevents sister chromatid separation.
- D.
Colchicine induces the loss of a single chromosome (monosomy) by destroying the kinetochore, whereas stochastic non-disjunction leads to whole genome duplication.
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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
Aneuploidy_vs_Polyploidy|Meiotic_Arrest_Points|Microtubule_Dynamics
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students frequently confuse the outcomes of cell-wide spindle failure (Polyploidy) with individual chromosome segregation errors (Aneuploidy).
The trap lies in assuming any 'segregation failure' automatically results in standard aneuploidy (like Down's syndrome), failing to recognize that colchicine causes a total systemic collapse of the spindle, shifting the entire ploidy level.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Principles of Inheritance and Variation - Class 12 |
| Concept | Aneuploidy vs Polyploidy |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |