The purpose of DNA replication in cell division is to ensure that each new cell receives an identical copy of the genetic material. During the cell cycle, specifically in the S phase, the DNA double helix unwinds, and each strand serves as a template for synthesizing a new complementary strand. This process is essential for maintaining genetic consistency during mitosis or meiosis, allowing for proper functioning and development of the organism. Errors in replication can lead to genetic mutations and potential diseases.