Question

A cell at the 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 the telophase stage. There is no formation of a cell plate and thus the cell is containing more chromosomes as compared to other dividing cells. This would result in-

• A. polyteny
• B. somaclonal variation
• C. polyploidy
• D. aneuploidy

Answer 1

The correct option is C

polyploidy

The correct option is C.

Explanation of correct option:

1. Nuclear division or karyokinesis is followed by cytoplasmic division or cytokinesis.
2. Cytokinesis is required for the formation of two daughter cells.
3. In-plant cells, cytokinesis involves the formation of a cell plate that represents the middle lamella.
4. If cell plate formation doesn’t take place, cytokinesis will be incomplete, and two daughter cells will not be formed.
5. This results in the formation of a single cell containing double the number of chromosomes. This condition is known as polyploidy.

Explanation of incorrect option:

Option A:

1. Polyteny refers to a condition in which DNA constantly replicates without separation.
2. This results in the formation of a giant chromosome called the polytene chromosome.

Option B:

1. Somaclonal variation is a phenomenon observed in plant tissue culture.
2. The variation occurs due to chromosomal rearrangements.

Option D:

1. Aneuploidy is a condition characterized by the gain or loss of one or more chromosomes.
2. It occurs when chromatids fail to segregate during cell division.

Final answer: A cell at the telophase stage shows no formation of a cell plate and contains more chromosomes as compared to other dividing cells. This would result in polyploidy.