The cell cycle is a series of events that take place in a living organism's cells, leading to their growth and division. It consists of four main phases - G1 (Gap 1), S (Synthesis), G2 (Gap 2) and M (Mitosis). During the G1 phase, the cell grows in size; during the S phase, it replicates its DNA; during the G2 phase, it continues to grow and prepares for mitosis or cell division. The final stage is mitosis, where the cell divides into two identical daughter cells, each containing a copy of their parent's genetic material. This process ensures that organisms can replace damaged or dead cells with new ones, allowing them to maintain tissue and organ function throughout their lives.