The cell cycle, an essential sequence of events, promotes cellular division and tissue growth. The cell cycle consists of four phases, each of which is unique and vital for cellular survival. This four-phase process includes the synthesis (S), mitosis (M), GAP 1 (G 1 ), and GAP 2 (G 2 ) phases (see figure below). During the mitosis (cellular division) phase, which lasts about 1 hour, the chromatids (i.e., daughter strands of a duplicated chromosome) split to form two identical cells. Mitosis consists of a five-phase progression that leads to the final separation of all intracellular components and the formation of two new daughter cells. Each daughter cell consists of a complete identical set of chromosomes and the essential components of the original cell. On completion of mitosis, the cell either begins a new cycle by entering the GAP 1 phase or proceeds to the G 0 phase, also called resting the stage or quiescence.