Figure 2: Cell cycle and its control. G0 stands for gap 0, G1 for gap 1, S for synthesis, G2 for gap 2, and M for mitosis. Cell cycle includes interface (G1, S, and G2), and M (including prophase, metaphase, anaphase, and telophase). Nondividing cells (G0 or resting phase) are not considered to be in the cell cycle. Cytokinesis follows mitosis. Checkpoint G1/S decides if cells go to rest (G0) or to S. Checkpoint G2/M decides if cells can begin mitosis. Checkpoint M occurs in metaphase of mitosis and it is in charge of biorientation.