During interphase, a cell undergoes significant growth, duplicates its DNA, and prepares for the process of cell division.

Interphase constitutes the longest phase of the cell cycle, accounting for approximately $90\%$ of the total duration. This phase is characterized by growth and preparation for cell division, and it is further divided into three distinct stages: G1 (first gap), S (synthesis), and G2 (second gap).

In the G1 phase, the cell experiences growth and performs its regular functions. Additionally, this stage involves a critical assessment of the surrounding environment to determine if conditions are favorable for division. If the environment is not suitable, the cell can enter a resting state known as G0, where it may remain for extended periods, potentially lasting years.

The S phase is dedicated to the duplication of the cell’s DNA. During this stage, each chromosome is replicated to form two identical copies, referred to as sister chromatids. These sister chromatids are essential for the subsequent division of the cell into two identical daughter cells during mitosis. Furthermore, the cell also duplicates its centrosomes, which play a crucial role in the cell division process.

In the G2 phase, the cell continues its growth and further prepares for mitosis. This includes the production of proteins and organelles, as well as a thorough check of the DNA for any potential damage. If any errors are detected, the cell will attempt to repair them prior to proceeding with mitosis.

Interphase is vital to the overall cell cycle, as it ensures that the cell is fully prepared to divide and that the resulting daughter cells will be identical to the parent cell. This phase is marked by intense activity, despite the perception that the cell is merely ‘resting.’ Without interphase, cells would be unable to grow, replicate their DNA, or prepare adequately for division—processes that are essential for the survival and growth of all organisms.