Before a cell can begin mitosis it must grow and create proteins, RNA and copies of DNA. These activities occur in a stage of the cell cycle called interphase.
Interphase is the longest stage of the cell cycle and is divided into three main phases. The first phase is called G1 phase. In G1 phase, the cell increases its mass and the number of cell organelles. S phase occurs after G1 phase and is the period during which DNA is copied. G2 phase occurs just prior to mitosis. It is a phase in which the cell continues to grow and produce more proteins.
Once interphase is complete, mitosis begins. During mitosis, the cell divides the contents of the nucleus between two daughter cells. Chromosomes form during prophase and the nuclear envelope dissolves. These chromosomes move to the middle of the cell during metaphase, followed by the process of separating the copies of the chromosomes during anaphase. The final stage of mitosis is telophase, which involves the formation of two nuclear envelopes around the two sets of chromosomes.
Mitosis is followed by a stage of the cell cycle known as cytokinesis. During cytokinesis, the cell divides the organelles and the cytoplasm between the two new daughter cells, completing the process of cell division.