During the S phase of the cell cycle, DNA replication occurs, leading to the formation of sister chromatids. Since each chromosome consists of two sister chromatids after replication, the number of chromatids will be twice the number of chromosomes.
If a cell has 24 chromosomes during G1, after S phase, there will be 24 pairs of sister chromatids, resulting in a total of 48 chromatids. Each chromosome has undergone DNA replication, producing two identical sister chromatids attached at the centromere.
