Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
mitosis1.notebook October 17, 2013 Mitosis division of the cell nucleus and its contents. 1 mitosis1.notebook October 17, 2013 Prophase longest stage of mitosis Centromere Sister chromatids Long, stringy chromatin coil up into visible chromosomes. 1. At the beginning of prophase the nucleus begins to disappear. nuclear envelope and nucleolus disintegrate. 2. In animal cells, centrioles begin to migrate to opposite ends of the cell and spindle fibers begin to form. Animal Cell Plant Cell 2 mitosis1.notebook October 17, 2013 Metaphase 1. Chromosomes attach to the spindle fibers by the centromere. 2. Line up on the equator of the cell. 3. Each sister chromatid is attached to its own spindle fiber. 4. One sister's chromatid spindle fiber extends to one pole and the other to the opposite pole. 5. Important because it ensures each new cell receives an identical and complete set of chromosomes. 3 mitosis1.notebook October 17, 2013 Anaphase 1. Centromeres split apart and the chromatid pairs from each chromosome separate. 2. Pulled to opposite poles. 3. Chromatids are pulled apart by the shortening the spindle fibers. 4 mitosis1.notebook October 17, 2013 Telophase 1. Nuclear membranes start to form. 2. Chromosomes unwind. 3. Spindle fibers break down. 4. Cytokinesis begins 5 mitosis1.notebook October 17, 2013 Cytokinesis Cytokinesis Division of cytoplasm. Occurs near the end of telophase. Animal cells: The plasma membrane pinches in along the equator and the cells divide. Plant cells: A cell plate is laid down across the equator. A plasma membrane forms around each cell and a new cell wall forms on either side of the plate until separation is complete. 6 mitosis1.notebook October 17, 2013 Important: Not all cells undergo mitosis. Mature roots, leaves and stems of plants Nerve cells and adult bone cells Singlecelled organisms use mitosis to reproduce. Multicellular organisms use mitosis for growth, development and repair. End Result: 2 genetically identical daughter cells. 7 mitosis1.notebook October 17, 2013 8