Stages of Interphase

During interphase, the cell undergoes normal growth processes while also preparing for cell division. It is the longest phase of the cell cycle, cell spends approximately 90% of its time in this phase.  In order for a cell to move from interphase into the mitotic phase, many internal and external conditions must be met.

The three stages of interphase are called G₁, S, and G₂.

G₁ Phase (First Gap)

The first stage of interphase is called the G₁ phase (first gap) where the cell is quite active at the biochemical level. The cell is accumulating the building blocks of chromosomal DNA and the associated proteins as well as accumulating sufficient energy reserves to complete the task of replicating each chromosome in the nucleus.

S Phase (Synthesis of DNA)

In the S phase, DNA replication results in the formation of identical pairs of DNA molecules—sister chromatids—that are firmly attached to the centromeric region.

G₂ Phase (Second Gap)

In the G₂ phase, the cell replenishes its energy stores and synthesizes proteins necessary for chromosome manipulation. Some cell organelles are duplicated, and the cytoskeleton is dismantled to provide resources for the mitotic phase.