During interphase, which is composed of the G1 phase, S phase and G2 phase, the cell grows and replicates its DNA and some of its organelles. During the S phase, the genetic material is duplicated into two sister chromatids, and centrosomes, which are nucleated microtubules that interact with the chromosomes to form the mitotic spindle, are also replicated. Metaphase is the third phase of mitosis, where sister chromatids align in the middle of the cell before their separation into two daughter cells.
