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 containing more number of chromosomes as compared to other dividing cells. This would result in:
Answer: (B) Polyploidy. Answer: (B) Polyploidy Solution: Absence of cell-plate (cytokinesis) formation after telophase means the duplicated chromosome set is not partitioned into two cells, so the single cell ends up with an extra whole set of chromosomes.
- A.Aneuploidy
- B.Polyploidy✓
- C.Somaclonal variation
- D.Polyteny
Correct Answer
(B) Polyploidy
Solution & Explanation
Answer: (B) Polyploidy Solution: Absence of cell-plate (cytokinesis) formation after telophase means the duplicated chromosome set is not partitioned into two cells, so the single cell ends up with an extra whole set of chromosomes. An increase in a whole set of chromosomes is called polyploidy, a condition often seen in plants. (Aneuploidy is gain/loss of single chromosomes, not whole sets.) NCERT Reference: NCERT Class XII, Ch 4, p.75, lines 43-46: "Failure of cytokinesis after telophase stage of cell division results in an increase in a whole set of chromosomes in an organism and, this phenomenon is known as polyploidy. This condition is often seen in plants."