The cell cycle is a series of stages that a cell goes through to grow and divide. It consists of four main phases: G1 phase, where the cell grows; S phase, where DNA is replicated; G2 phase, where the cell prepares for division; and M phase, where the cell divides into two daughter cells. Each phase is crucial for ensuring that the new cells are healthy and have the correct amount of DNA. The cycle is tightly regulated by various proteins and checkpoints to prevent errors, which can lead to issues like cancer if not properly managed.