Cytokinesis (2 nd part of M phase) TWO new nuclei are now in one cytoplasm Cytokinesis: Division of the cytoplasm Animal Cells: The membrane pinches inward and splits the cell in two Plant Cells: A cell plate forms across the center of the cell to divide the cell wall. Cytokinesis usually occurs the same time as telophase

Mitosis Animation

During Prophase: Chromatin condenses into chromosomes. The nucleus begins to disappear Spindle fibers begin to form at centrioles During Metaphase: Chromosomes move to the center of the cell Centrioles migrate to opposite ends of the cell Spindle fibers attach to the chromosomes at the centromere During Anaphase: Sister Chromatids are pulled apart by spindle fibers (microtubules) connected to the centromere Nucleus begins to re-form During Telophase: Cleavage furrow forms Nucleus continues to form Cytokinesis Occurs (cells actually divide) Two diploid cells have been formed Mitosis – 4 Stages of Cell Division

Homologous chromosomes – sets of chromosomes where one comes from the male parent and the other from the female. Humans have 46 chromosome 23 from Mom + 23 from Dad = 23 homologous pairs Homologous chromosomes are the same size Homologous chromosomes contain the same genes Meiosis

Diploid: cells that have a full set of chromosomes. Abbreviated: 2N In humans, diploid cells have 46 chromosomes. Almost all cells in the human body are diploid. Meiosis

Haploid: cells that have ½ the number of chromosomes. Cells contain only 1 chromosome from each homologous chromosomes. In humans, haploid cells have 23 chromosomes In humans, the only haploid cells are sperm and egg cells. Meiosis