Transcript File
Mitosis 1 Mitosis division of the nucleus only occurs in eukaryotes has four stages doesn’t occur in some cells such as brain cells 2 Four Mitotic Stages Prophase Metaphase Anaphase Telophase PMAT! 3 Early Prophase chromatin in nucleus condenses to form visible chromosomes spindle forms from fibers in cytoskeleton or centrioles (animal) Nucleolus Cytoplasm Nuclear Membrane Chromosomes 4 Late Prophase nuclear membrane & nucleolus are broken down chromosomes continue condensing & are clearly visible spindle fibers attach to the centromere of each chromosome spindle finishes forming between the poles of the cell 5 Late Prophase Chromosomes Nucleus & Nucleolus have disintegrated 6 Sketch The Spindle Centromere Centriole Spindle fiber 7 Metaphase chromosomes, attached to the spindle fibers, move to the center of the cell chromosomes are now lined up at the equator Equator of Cell Pole of the Cell 8 Metaphase Spindle fibers Chromosomes at Equator 9 Metaphase spindle fibers spindle fibers chromosomes lined at the equator chromosomes lined at the equator 10 Anaphase occurs rapidly chromatids are pulled apart to opposite poles of the cell by spindle fibers 11 Anaphase chromatids being separated chromatids being separated 12 Telophase chromatids at opposite poles spindle disassembles nuclear envelope forms around each set of chromatids to make two nuclei nucleolus reappears in new nuclei chromosomes reappear as chromatin 13 chromatids now back as chromatin 14 Cytokinesis means division of the cytoplasm division of cell into two, identical halves called daughter cells in plant cells, cell plate forms at the equator to divide cell in animal cells, belt of protein fibers splits the cell 15 Cytokinesis belt of fibers in animal cell cell plate in plant cell 16 Daughter Cells of Mitosis have the same number of chromosomes as each other & as the parent cell from which they were formed identical to each other, but smaller than parent cell must grow in size to become mature cells (G1 of Interphase) 17 Review of Mitosis 18 Name the Stages Interphase Telophase Prophase Metaphase Anaphase 19 ? Early, Middle, & Late Prophase ? ? Metaphase Late Prophase Late Anaphase Anaphase ? ? Telophase ? ? 20 Late Telophase Uncontrolled Mitosis if mitosis is not controlled, unlimited cell division – this is cancer masses of cancer cells cause tumors which invade surrounding healthy tissue not all tumors are cancerous – some DON’T invade healthy tissue cancer cells 21 22