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: Polyploidy Solution: If the cell-plate (cytokinesis) fails to form at telophase, karyokinesis is not followed by cytoplasmic division, so both daughter chromosome sets remain in a single cell, giving it a complete extra set of chromosomes, i.e., polyploidy.
- A.Aneuploidy
- B.Polyploidy✓
- C.Somaclonal variation
- D.Polyteny
Correct Answer
(B) Polyploidy
Solution & Explanation
Answer: Polyploidy Solution: If the cell-plate (cytokinesis) fails to form at telophase, karyokinesis is not followed by cytoplasmic division, so both daughter chromosome sets remain in a single cell, giving it a complete extra set of chromosomes, i.e., polyploidy. Aneuploidy is gain or loss of one or a few individual chromosomes, not whole sets. Polyteny is repeated DNA replication without separation of chromatids, and somaclonal variation is tissue-culture-derived genetic variation, neither of which is caused by simple cell-plate failure. NCERT Reference: Ch 10, p.124, lines 37-38 — "called the cell-plate that"