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Question #45301
The Question
During megasporogenesis in a typical angiosperm exhibiting Polygonum-type development, the Megaspore Mother Cell (MMC) undergoes meiosis. Unlike typical somatic cell divisions, this process involves specific cytokinetic modifications. Which of the following statements correctly explains the cytological basis for the spatial arrangement and subsequent asymmetry of the resulting megaspores?
Options
- A.
The phragmoplast aligns parallel to the micropylar-chalazal axis during both meiotic divisions, resulting in a tetrahedral arrangement of megaspores.
- B.
Cytokinesis is strictly transverse during both meiotic divisions, establishing a linear tetrad where the chalazal megaspore retains the maximum developmental potential.
- C.
The equational division (Meiosis II) is characterized by symmetric cytokinetic partitioning, giving all four megaspores equal viability before external hormonal signals induce degeneration.
- D.
Meiosis in the MMC is immediately followed by free nuclear divisions without cell plate formation, creating a coenocytic tetrad before cellularization occurs.
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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
Equational Division Logic|Megasporogenesis Symmetry|Plant Cell Cytokinesis
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between the cellular divisions of megasporogenesis (which require transverse cytokinesis to form a linear tetrad) and the free-nuclear divisions of megagametogenesis.
Common Misconception: Students often assume all meiotic divisions (especially the equational Meiosis II) are perfectly symmetric in potential, ignoring the strict spatial and cytoplasmic asymmetry dictated by the micropylar-chalazal axis in plant embryology.
Furthermore, students frequently confuse the timing of cell plate formation, mixing up sporogenesis (successive cytokinesis) with gametogenesis (free-nuclear).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell Cycle and Cell Division - Class 11 |
| Concept | Plant Cell Cytokinesis |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |