Question -
Answer -
i) Yes, DNA replication can take place in G1 phase of cell cycle. The number of chromosomes remain the same and each chromosome is formed from one chromatid. In the S phase, chromosome is formed by two sister chromatids joined at the centromere. Similar conditions continue in the G2 phase, while in M phase, sister chromatids separate and move to different cells. The number of chromosomes stays the same in mitosis.
ii) Amount of DNA content in the cell remains the same in G1 phase but in S phase it doubles as the DNA replication takes place. It remains double in G2 phase but halved in the M phase of the cell cycle.