DNA replication occurs during the S phase (synthesis phase) of the cell cycle.
The cell cycle is the series of events that occurs in a cell as it grows and divides into two daughter cells. It consists of two main phases: interphase and the cell division phase.
Interphase is further divided into three subphases: G1, S, and G2. During G1 phase, the cell grows and carries out its normal functions. In S phase, DNA replication occurs, and the cell’s DNA is replicated. Finally, in G2 phase, the cell prepares for cell division by synthesizing proteins and other components needed for division.
In summary, DNA replication occurs during S phase, which is the second subphase of interphase, preceding the cell division phase.