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  1. 1. No Bellringer This Week
  2. 2. Agenda <ul><li>NOTES: Mitosis </li></ul><ul><ul><li>Details of Chromosome Structure </li></ul></ul><ul><ul><li>Organelles Involved in Division </li></ul></ul><ul><ul><li>Mnemonic Device for PMATC </li></ul></ul><ul><ul><li>Details of each step of Mitosis </li></ul></ul>
  3. 3. Structure of Chromosomes <ul><li>Chromosomes are tightly packed bundles of DNA that look like the letter X. </li></ul><ul><li>The left and right halves of chromosomes are identical strands called “Sister Chromatids”. </li></ul><ul><li>The spot where the chromatids connect together is called the centromere. </li></ul>
  4. 4. Chromosomes
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  7. 7. Nuclear Membrane <ul><li>The Nuclear Membrane is the outer skin of the nucleus. </li></ul><ul><li>It is the the “Sac” that holds Chromatin. </li></ul><ul><li>It is sometimes called the Nuclear Envelope. </li></ul>
  8. 8. Cytoskeleton <ul><li>The cytoskeleton is a network of protein fibers that run throughout the cell. </li></ul><ul><li>These fibers maintain the shape of a cell and act as tiny muscles to stretch and move. </li></ul>
  9. 9. BLUE = Microtubules GREEN = Intermediate Filaments RED = Microfilaments
  10. 10. Mitotic Spindle <ul><li>The mitotic spindle is a collection of fibers that pull chromosomes apart during mitosis. </li></ul><ul><li>It has 3 major components </li></ul><ul><ul><li>Centrioles: A pair of organelles that anchor the mitotic spindle at opposite ends of the cell. </li></ul></ul><ul><ul><li>Asters: Short fibers that radiate out from the centrioles in order to hold their position </li></ul></ul><ul><ul><li>Kinetechore fibers: Long fibers that pull chromosomes apart and toward either end of cell. </li></ul></ul>
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  12. 12. Steps of Mitosis <ul><li>Mitosis is the division of Eukaryotic Cells. </li></ul><ul><li>It has 5 steps </li></ul><ul><ul><li>Prophase </li></ul></ul><ul><ul><li>Metaphase </li></ul></ul><ul><ul><li>Anaphase </li></ul></ul><ul><ul><li>Telophase </li></ul></ul><ul><ul><li>Cytokinesis </li></ul></ul>
  13. 13. Pass Me Another Tasty Cupcake
  14. 14. Pimps Make All That Cash
  15. 15. Pet My Alligator, Tom Cruise
  16. 16. P.M.A.T.C. <ul><li>Pass Me Another Tasty Cupcake </li></ul><ul><li>Pimps Make All That Cash </li></ul><ul><li>Pet My Alligator, Tom Cruise </li></ul>
  17. 17. Prophase <ul><li>Chromatin in the DNA coils to make chromosomes </li></ul><ul><li>The nuclear membrane breaks down, releasing chromosomes into the cytoplasm </li></ul><ul><li>Centrioles move to opposite ends of the cell and the mitotic spindle forms between them. </li></ul><ul><li>Kinetechore fibers from each half of the spindle attach to the centromere region of each chromosome. </li></ul>
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  20. 20. Metaphase <ul><li>Kinetechore fibers of the spindle move chromosomes towards center of the cell. </li></ul><ul><li>By the end of this phase all chromosomes are lined up along the “equator”. </li></ul>
  21. 21. Metaphase Chromosomes lined at the Equator Asters at the poles Spindle Fibers
  22. 22.
  23. 23. Anaphase <ul><li>Chromosomes are split apart and Sister chromatids are pulled in opposite directions </li></ul><ul><li>This occurs very quickly ( Less than 5 minutes ) </li></ul>
  24. 24. Anaphase Sister Chromatids being separated
  25. 25. Telophase <ul><li>Sister chromatids arrive at opposite ends of the cell and begin converting back into chromatin. </li></ul><ul><li>A nuclear envelope forms around each set of DNA to create new nuclei. </li></ul><ul><li>The mitotic spindle is broken down. </li></ul>
  26. 26.
  27. 27. Cytokinesis <ul><li>The Cell Membrane pinches together between the 2 newly formed nuclei </li></ul><ul><li>This movement is done by the cytoskeleton. </li></ul>
  28. 28. BrainPOP: Mitosis
  29. 29. Assignment <ul><li>17 review questions </li></ul><ul><li>Due Tomorrow </li></ul>