The longest stage of the cell cycle is interphase/10%3A_Cell_Reproduction/10.02%3A_The_Cell_Cycle/10.2A%3A_Interphase). Interphase is the phase of the cell cycle in which a typical cell spends most of its life. During interphase, the cell grows and copies its DNA in preparation for mitosis/10%3A_Cell_Reproduction/10.02%3A_The_Cell_Cycle/10.2A%3A_Interphase). Interphase consists of three subphases: G1, S-phase, and G2, and G1 is the longest phase of interphase/10%3A_Cell_Reproduction/10.02%3A_The_Cell_Cycle/10.2A%3A_Interphase). During the S-phase, DNA replication occurs, which takes the longest time because of the complexity of the genetic material being duplicated/10%3A_Cell_Reproduction/10.02%3A_The_Cell_Cycle/10.2A%3A_Interphase).