Cell cycle is the series of events in which cells replicate and make two new cells. Cell cycle consists of stages- G1, S,G2, and M (karyokinesis). G1 is the stage where the cell is preparing to divide. It then moves into the S phase where the cell copies all the DNA. S stands for synthesis phase (of DNA). After the DNA is copied and there's a complete extra set of all the genetic material, the cell moves into the G2 stage, where it organizes and condenses the genetic material, or starts to condense the genetic material, and prepares to divide. The next stage is M. M stands for mitosis. It is further divides into four stages, Related Theory Some cells enter G0 temporarily until an external signal triggers the onset of Gr. Other cells that never or rarely divide, such as mature cardiac muscle and nerve cells, remain in G0 permanently. A Caution There is a confusion in the events of Gap-1 and Gap-2 phases. [Mnemonic: G2 phase two - twins - Protwins (Proteins)]