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Question #45275

Difficulty: 8/10 | 🟢 Free

The Question

A researcher treats a rapidly dividing meristematic tissue of an angiosperm ( $2n = 14$ ) with a chemical agent that specifically binds to tubulin dimers, preventing their polymerization. Which of the following accurately describes the immediate cytological consequence and the ultimate ploidy level of the resulting cells if the cell cycle eventually bypasses the checkpoint without cytokinesis?

Options

A.
Arrest at metaphase due to failure of kinetochore microtubule assembly, ultimately leading to polyploidy ( $4n = 28$ ).
B.
Arrest at anaphase due to the inability of spindle fibers to depolymerize, leading to aneuploidy ( $2n+1$ or $2n-1$ ).
C.
Arrest at telophase due to the failure of phragmoplast formation, resulting in a multinucleate syncytium ( $2n = 14$ ).
D.
Arrest at prophase due to the inhibition of chromosome condensation, leading to endoreduplication ( $4n = 28$ ).

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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

Terminalization of Chiasmata|Mitotic Index Implications|Colchicine-like interference

Why This Question Is Tricky

Common Mistakes

Conceptual Pivot: Understanding that spindle poisons trigger the Spindle Assembly Checkpoint (SAC) causing Metaphase arrest, not Anaphase arrest.

Common Misconception: Students often confuse the failure of chromosome separation (which implies Anaphase failure) with the actual stage of arrest (Metaphase) and frequently mix up Polyploidy (whole genome duplication) with Aneuploidy (individual chromosome gain/loss).

Quick Facts About This Question

Question Information

Subject	Biology
Chapter	Cell Cycle and Cell Division - Class 11
Concept	Terminalization of Chiasmata
Difficulty	8
Cognitive Load	5
Target Solve Time	120 sec
Access	Free