List the four phases of mitosis, and briefly explain what occurs during each phase.
Prophase: the chromatin coils and produces chromosomes, the nucleolus and nuclear envelope disappear, and the mitotic spindle forms. Metaphase: kinetochore fibers move the chromosomes to the cell equator. Anaphase: the chromatids in every chromosome separate and move toward opposite poles of the cell. Telophase: the mitotic spindle disappears, the chromatids unwind to form chromatin, the nuclear envelope reforms, and a nucleolus appears.