The main purpose of interphase in the eukaryotic cell is the replication of DNA which occurs during it.
Interphase (resting phase) is the phase of the cell cycle in which cell copies its DNA. Interphase is the longest phase of cell cycle and during this phase, cell prepares for mitosis (interphase is not the first stage of mitosis). Preparing for mitosis means that cell conducts its normal functions like obtaining nutrients and metabolizing them, growing, reading its DNA.
There are three stages of interphase:
1. G1 (Gap 1)- During this stage, the cell grows to about double its original size synthesize more protein, more organelles and the volume of the cytoplasm increases.
2. S phase (Synthesis)- During this phase cell duplicates its DNA.
3. G2 (Gap 2)- During this phase cell is continuing with preparation.
If the cells don’t divide they residue in a terminal G₀ phase.
Between each phase, there is a checkpoint where the accuracy of the previous phase is checked before proceeding to the next.