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Question #46974
The Question
A culture of actively feeding ciliated protozoans (Paramecium) is treated with an effective concentration of colchicine. Which of the following represents the most immediate physiological consequence observed in these organisms and its correct underlying molecular mechanism?
Options
- A.
Cessation of food ingestion and motility due to the inhibition of tubulin polymerization, disrupting the 9+2 axonemal microtubule dynamics.
- B.
Immediate osmotic lysis due to the disruption of the microtubule-dependent contractile vacuole complex.
- C.
Arrest of binary fission at anaphase due to the depolymerization of actin microfilaments in the mitotic spindle.
- D.
Paralysis of ciliary beat due to the direct competitive inhibition of dynein ATPase by colchicine.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Rivet Popper Hypothesis|Slime Mold Aggregation|Alien Species Invasion Impacts
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize colchicine strictly as a 'mitotic poison' (arresting cell division at metaphase) without understanding its fundamental molecular target: tubulin.
This question tests the ability to extrapolate that any structure relying on microtubules (like the 9+2 axoneme of cilia) will be functionally compromised by tubulin-binding agents, thereby linking Cell Biology (cytoskeleton) with Biological Classification (protozoan physiology).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biological Classification - Class 11 |
| Concept | Slime Mold Aggregation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |