It also duplicates an organizational structure called the centrosome. Centrosomes help separate DNA during the M phase. In the G2 phase, the cell grows more, produces more proteins and organelles, and begins to rearrange its contents in preparation for mitosis. The G2 phase ends when mitosis begins. The combination of G1, G2 and S phases is known as interphase. Interphase occurs between one mitotic phase and the next. In the M phase, the cell divides the copied DNA and cytoplasm to create two new cells. It involves two distinct processes related to division. Mitosis and cytokinesis. In mitosis, the cell's nuclear DNA condenses into visible chromosomes and is separated by the mitotic spindle, a structure made of microtubules. Mitosis occurs in four phases: prophase, metaphase, anaphase and telophase. Different cells take different times to complete the cell cycle. A human cell could take a full 24 hours to divide. Different cell types also divide their time between cell cycle phases in different ways. Cancer is a disease in which cell cycle regulation goes awry and the normal growth and behavior of cells goes awry