When does DNA replication happen during cell division?

DNA replication happens during interphase before cell division occurs. Interphase is the phase of the cell cycle where the cell grows and prepares for division, and it is divided into three phases: G1, S, and G2. DNA replication specifically takes place during the S phase of interphase. This is essential to ensure that the cell has two complete sets of chromosomes before it enters mitosis or meiosis, where the cell divides into two (mitosis) or four (meiosis) daughter cells.