Mitosis

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Mitosis

• Anatomy and Physiology

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Mitosis

• Division of nucleus that results in 2 identical
  daughter cells

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Which cells ?

• Eukaryotic somatic cells undergo mitosis

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Why?

• Cells undergo mitosis to replace dead or dying
  cells
• The cells are replaced by identical cells which
  have identical functions as the cell being
  replaced

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When?

• Human cells undergo mitosis on the average of
  every 48 hours

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How?

• Mitosis is part of the cells life cycle
• The cells life cycle includes the following
• Interphase
• Mitosis
• cytokinesis

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The Cell Cycle
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Interphase

• The longest phase of the cell cycle
• Approx. 70-75 of life of cell is spent in
  interphase
• 3 phases in Interphase

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Phases of Interphase

• G1 - intense cell growth, cells contents
  duplicated
• S - DNA is synthesized
• G2 - more growth and preparation for cell division

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Mitosis

• Mitosis is the nuclear division of a cell that
  results in 2 identical cells.
• 4 phases of mitosis
• 1. Prophase
• 2. Metaphase
• 3. Anaphase
• 4. Telophase

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Prophase

• Nuclear membrane disintegrates
• Nucleolus disappears
• Chromatin takes on the form of linear chromosomes
  (sister chromosomes which are homologous)
• Chromosomes are visible
• Centrioles split and move to opposite sides

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Sister Chromosomes
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Prophase
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Prophase
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Metaphase

• Sister chromosomes (dyads) lined up in the middle
  of the cell (equator) with the help of spindle
  fibers
• Spindle fibers released from centrioles

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Metaphase
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Metaphase (plant cell)
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Anaphase

• Homologous Sister chromatids pulled apart to
  opposite sides
• Spindle fibers shorten
• Furrow develops (in late anaphase)
• Cell elongates

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Anaphase
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Anaphase
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Telophase/cytokinesis

• Nucleus reappears (split from each other)
• Nucleolus reappears
• Chromosomes no longer visible (now called
  chromatin)
• Cytoplasm divided equally (cytokinesis)
• 2 identical daughter cells formed

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Telophase
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Telophase
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Video links

• http//www.youtube.com/watch?vnPG6480RQo0feature
  related
• http//www.youtube.com/watch?vAhgRhXl7w_g

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Mitosis out of control

• http//www.youtube.com/watch?v_ZEysIhDsokfeature
  PlayListp95B92DDF5E02DF3Aindex44

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THE END
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