When does DNA replication occur during cell division?

DNA replication occurs before cell division, specifically during the S phase of interphase, which is part of the cell cycle. The cell undergoes replication of its DNA to ensure that each daughter cell receives a complete set of genetic material. After the S phase, the cell progresses through the G2 phase, where it checks for errors in the DNA before entering mitosis (or meiosis in reproductive cells) for actual cell division. This ensures that the genetic content is accurately passed on during division.