Cell Cycle Tools A B Mitosis division of the nucleus Cytokinesis division of the cytoplasm Cell cycle The period between one cell division and the next prophase centriole move to the poles of the cell; chromosomes and spindle fibers appear; and nucleolus and nuclear membrane disappear metaphase chromosomes line up along the equator of the cell anaphase chromatids split and move to the poles of the cell telophase chromosomes and spindle fibers disappear and nucleolus and nuclear membrane appear chromatin string-like DNA chromosome tightly coiled DNA and histones histones special proteins found in chromosomes centromere structures that hold chromatids together chromatids sides of a chromosome that are identical to each other asters and centrioles structure that appear during animal cell mitosis cell plate structure that appears during cytokinesis of a plant cell; cell wall forms off of this cell furrow the pinching in of the cell membrane during cytokinesis of a animal cell Why cells divide? As a cell grows the volume(cytoplasm and organelles) of a cell increases faster than the surface area(cell membrane);meaning the cell membrane can not provide all of the cell with the nutrients it needs or get rid of wastes fast enough Cancer uncontrolled cell division Nucleosome bead-like structures of DNA and histones Interphase Cell nondivision= G1, S, and G2 G1 period in interphase where the cell is growing and developing S DNA synthesis or replication that occurs during interphase G2 period in interphase where the cell is preparing to divide by making more proteins, organelles and energy