The fruit fly has 8 chromosomes (2n) in each cell. During interphase of Mitosis if the number of chromosomes at G1 phase is 8, what would be the number of chromosomes after S phase?
- 32
- 8
- 16
- 4
Answer
(2) 8
Solution
As per NCERT, during S phase the amount of DNA per cell doubles (2C → 4C), but there is no increase in the chromosome number.
⇒ Each chromosome now has two sister chromatids held at one centromere.
∴ Number of chromosomes after S phase = 8 (2n remains 2n).
Answer: (2)