Question

A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that this cell is not like other cells at telophase stage. There is no formation of cell plate and thus the cell is contaning more number of chromosomes as compared to other dividing cells. This would results in

• A. Polyploidy
• B. Somaclonal variation
• C. Polyteny
• D. Aneuploidy

Answer 1

The Correct Option is A

To solve this question, we first need to understand the processes involved in cell division and identify what the observation of "no formation of cell plate" and "more number of chromosomes" indicates.

1. The cell cycle consists of several stages: interphase (which includes G1, S, and G2 phases) and the mitotic phase (M phase), which includes prophase, metaphase, anaphase, and telophase.
2. During telophase, the cell typically undergoes cytokinesis, which results in the formation of two daughter cells. In plant cells, this involves the formation of a cell plate that eventually develops into the cell wall.
3. However, in this specific scenario, the student observed that there was no cell plate formation, indicating that cytokinesis might not have occurred properly. This could lead to a cell containing more chromosomes than usual because the division of the cell has not physically taken place to create two separate cells.
4. The result of incomplete cytokinesis and having more chromosomes is commonly associated with the condition known as "polyploidy," where cells or organisms contain more than two complete sets of chromosomes.

Let's evaluate the options given:

1. Polyploidy: This describes cells with multiple sets of chromosomes. Given the observation of "more chromosomes" and "no cell plate," this is the likely result in this scenario.
2. Somaclonal variation: Refers to genetic variation that occurs in plants regenerated from somatic cells. This is not relevant in the context described.
3. Polyteny: Involves the replication of chromosomes without cell division, leading to large "chromosome bundles." This is not indicated by the lack of a cell plate in telophase.
4. Aneuploidy: Refers to the presence of an abnormal number of chromosomes, which generally results from non-disjunction during cell division. Incomplete cytokinesis leading to increase in chromosome sets is not directly related to aneuploidy.

Thus, the correct answer is "Polyploidy" as the observation aligns with the characteristics of that condition.