Before You Begin
Question #45263
The Question
A researcher treats an actively dividing animal cell culture with colchicine at the exact onset of prophase. Which of the following statements correctly identifies the status of the centrioles and the subsequent fate of the cell cycle?
Options
- A.
Centrioles fail to duplicate in the cytoplasm during the G2 phase, preventing chromosome condensation and leading to an immediate cell cycle arrest.
- B.
Centrioles, having already duplicated in the S phase, fail to migrate to opposite poles due to inhibited tubulin polymerization, resulting in metaphase arrest.
- C.
Centrioles migrate to opposite poles normally, but the inhibition of microtubule depolymerization prevents sister chromatid separation, causing anaphase arrest.
- D.
Centrioles, having duplicated in the M phase, fail to form an anastral spindle, leading to non-disjunction and subsequent aneuploidy.
Check Your Answer
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
Centriole Duplication Timing|Meristematic Totipotency|Mitotic Index Implications
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that 'colchicine causes polyploidy' but fail to connect the chronological sequence of the cell cycle.
The trap relies on confusing the timing of centriole duplication (S phase vs G2/M phase) and misunderstanding that centrosome migration itself is a microtubule-dependent process.
By introducing the poison at prophase, the question forces the student to recognize that S-phase events (DNA and centriole duplication) are already complete, isolating the failure strictly to spindle formation and metaphase-to-anaphase transition.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell Cycle and Cell Division - Class 11 |
| Concept | Centriole Duplication Timing |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |