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Question #46758
The Question
A novel chemical agent disrupts the Spindle Assembly Checkpoint (M-checkpoint) in human somatic cells by inhibiting the proteins that monitor kinetochore-microtubule attachment. Which of the following is the most likely downstream consequence of this disruption leading to malignant transformation?
Options
- A.
Arrest of the cell cycle in Metaphase due to the permanent inactivation of the Anaphase Promoting Complex (APC).
- B.
Failure of cytokinesis at the end of Telophase, leading to polyploidy and subsequent hyperactivation of telomerase.
- C.
Unequal chromosomal segregation resulting in aneuploidy, potentially causing the loss of heterozygosity for a tumor suppressor gene.
- D.
Direct structural alteration of DNA during the S-phase, converting cellular proto-oncogenes into active viral oncogenes.
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
Microtubule Dynamic Instability|Oncogenes vs Proto-oncogenes|Meiotic Reductional Division
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the 'activation' of a checkpoint (which arrests the cell cycle to fix errors) with the 'failure' of a checkpoint (which allows the cell to divide despite errors).
Additionally, this question tests the ability to distinguish between polyploidy (failure of cytokinesis) and aneuploidy (failure of segregation), and bridges the gap between a physical cytoskeletal defect in M-phase and the genetic basis of cancer (gene dosage/LOH).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell – The Unit of Life - Class 11 |
| Concept | Microtubule Dynamic Instability |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |