The Question is from neet-botany cell-cycle-and-cell-division meiosis, and it was created by the author Mr. NARESH KUMAR K

Question

In a plant species with a diploid number of 12, a mutation causes complete failure of cytokinesis following telophase II of meiosis. What would be the ploidy of the resulting megaspore?

Mr. NARESH KUMAR K · Accepted Answer

## CORE INFORMATION
✓ **Answer**: B
## CONCEPT FRAMEWORK
	**Primary Concept**: Meiosis and Cytokinesis
	**Related Topics**: Ploidy, Megaspore formation, Cell division
	**Prerequisites**: Understanding of meiosis stages, diploid and haploid cells, cytokinesis
## SOLUTION PATHWAY
**Given Information**:
	Diploid number (2n) = 12
	Cytokinesis fails after telophase II of meiosis.
**Method & Steps**:
	1. Normal Meiosis:
		Reasoning:  Meiosis typically produces four haploid cells from one diploid cell.
		Formula/Rule: Meiosis I separates homologous chromosomes, reducing ploidy from 2n to n. Meiosis II separates sister chromatids.
	2. Cytokinesis Failure:
		Working: If cytokinesis fails after telophase II, the two daughter nuclei resulting from meiosis II will remain in the same cell.
		Key Point: Each nucleus after meiosis II would normally have a haploid chromosome number (n).
	3. Resulting Ploidy:
		Result: With two haploid nuclei within a single cell, the resulting megaspore will have a diploid chromosome number (2n). Since 2n = 12, the megaspore will have 12 chromosomes.
		Verification: Two haploid (n=6) nuclei in one cell combine to form a diploid (2n=12) cell. 
 ## OPTION ANALYSIS
[A] :x: Haploid (n=6): This would be the normal ploidy of a megaspore after complete meiosis. However, cytokinesis failure prevents the separation into haploid cells.
[B] ✓: Diploid (2n=12):  Cytokinesis failure after telophase II results in a diploid megaspore because two haploid nuclei remain within the same cell.
[C] :x: Triploid (3n=18): This ploidy level is not possible with the given scenario.
[D] :x: Tetraploid (4n=24): This ploidy level is not possible with the given scenario.  It might result from failure of cytokinesis in mitosis of a diploid cell.
 ## LEARNING AIDS
	**Common Mistakes**:
		1. Confusing the products of meiosis I and meiosis II: Remember that meiosis I separates homologous chromosomes, while meiosis II separates sister chromatids.
		2.  Forgetting the effect of cytokinesis failure: Failure of cytokinesis leads to an increase in the number of chromosomes within a single cell.
	**Quick Tips**:
		1. Visualize the process of meiosis and cytokinesis to understand the outcome.
		2. Remember that 'n' represents the haploid chromosome number and '2n' represents the diploid chromosome number.

Mr. NARESH KUMAR K · Answer

Haploid (n=6)

Mr. NARESH KUMAR K · Answer

The correct Option is "Diploid (2n=12)"

Mr. NARESH KUMAR K · Answer

Triploid (3n=18)

Mr. NARESH KUMAR K · Answer

Tetraploid (4n=24)

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