<Li> Synthesis (S), in which the cell synthesize its DNA and chromosome number is doubled. (via semiconservative replication). </Li> <Li> G (Gap 2), in which the cell resumes its growth in preparation for division . The mitochondria divide and the cell continues to grow until mitosis begins . In plants, chloroplasts also divide during G2 . </Li> <Li> In addition, some cells that do not divide often or ever, enter a stage called G (Gap zero), which is either a stage separate from interphase or an extended G . </Li> <P> The duration of time spent in interphase and in each stage of interphase is variable and depends on both the type of cell and the species of organism it belongs to . Most cells of adult mammals spend about 24 hours in interphase; this accounts for about 90% - 96% of the total time involved in cell division . Interphase includes G1, S, and G2 phases . Mitosis and cytokinesis, however, are separate from interphase . In G1 phase decision for cell division is taking place . </P>

Between the interphase and mitosis cells can enter a stage called g0 in which they are quiescent