DNA Replication and DNA Storage Practice Test

DNA replication happens during the synthesis phase of the cell cycle. In this stage the cell duplicates its entire genome, using each old strand as a template to build a new complementary strand. This creates semi-conservative daughter DNA molecules, each with one old and one new strand, forming sister chromatids in preparation for mitosis. The other phases have different roles—G1 is about growth and nutrient check, G2 prepares the cell for division and checks for errors, and M drives chromosome condensation and separation. So the copying of DNA occurs specifically during the synthesis phase.