G1, S, and G2 are the three primary phases that make up the interphase process. During the G1 phase, also known as the first gap phase, the cell grows physically, multiplies organelles, and synthesizes the chemical building blocks it will need in subsequent phases. The initial step of interphase is referred to as the G1 phase because there is little change evident at the microscopic level (first gap). The cell is biochemically extremely active during the G1 stage, on the other hand. The cell is assembling the components of chromosomal DNA and associated proteins while also conserving energy so that each chromosome can be replicated in the nucleus. Throughout the interphase, nuclear DNA maintains a semi-condensed chromatin structure. In the S phase, DNA replication takes place, resulting in the formation of identical pairs of DNA molecules (sister chromatids) that are tightly linked.
