The cell cycle is divided into two phases - Interphase and Mitosis phase or the M phase. The interphase is further divide into 3 phases - Gap 1 or G1 phase, Synthesis phase or S phase and Gap 2 or ${\mathrm{G}}_2$ phase. ${\mathrm{G}}_1$ phase is the interval between mitosis and initiation of DNA replication during which the cell is metabolically active and grows but does not replicate. The DNA replication begins in the S phase and the centrioles duplicate in the cytoplasm. In the ${\mathrm{G}}_2$ phase, proteins are synthesised in preparation for mitosis while cell growth continues.