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Question #46217
The Question
A botanist treats the actively dividing root apical meristem of Ipomoea batatas with colchicine to increase its agricultural yield. Which of the following accurately describes the cellular mechanism of the chemical and the anatomical nature of the structure being modified?
Options
- A.
Colchicine prevents tubulin polymerization, arresting mitosis at metaphase, leading to polyploidy and cellular gigantism in the modified adventitious root.
- B.
Colchicine inhibits the action of separase during anaphase, leading to endoreduplication and increased starch storage in the modified tap root.
- C.
Colchicine prevents the formation of the cell plate during cytokinesis, creating a multinucleated syncytium that enhances the sink capacity of the adventitious root.
- D.
Colchicine binds directly to kinetochores to block microtubule attachment, inducing polyteny and subsequent gigantism in the modified tap root.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Root_Modifications|Prophase_I_Sub-stages_Sequence|Chromatin_Condensation_States
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: This question tests two distinct NCERT concepts simultaneously.
First, the morphological distinction between adventitious roots (Sweet potato) and tap roots (Carrot).
Second, the precise mechanism of colchicine: students often mistakenly believe it inhibits cytokinesis (leading to a syncytium), whereas it actually inhibits tubulin polymerization, arresting karyokinesis at metaphase.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Morphology of Flowering Plants - Class 11 |
| Concept | Root Modifications |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |