Mitosis

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Mitosis

• What is it?
• Why is it Important?
• What do I need to know?

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What is Mitosis?

• MITOSIS division of the nucleus into two
  identical daughter cells

http//fairmanstudios.com/als.htm
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Why is mitosis important?

• Eukaryotes use cell division to create new cells
• Growth, Maintenance and Repair of body cells
• Asexual cell division

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What makes up the cell cycle?
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• Chromosome made of a DNA and protein complex
  chromatinFollowing DNA replication, a chromosome
  contains two sister chromatids attached by a
  centromere

MITOSIS is about organizing and distributing
Sister
Chromosome
Chromatids
CHROMOSOMES
Centromere
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What happens in INTERPHASE?

• Cells are in interphase 90 of the time
• G1 Gap 1 (cell growth)
• S chromosome synthesis (duplication)
• G2 Gap 2 (cell growth)
• M Mitosis

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INTERPHASE
nucleolus (if any) still visible
nuclear envelope clearly visible
chromatin, NO chromosomes, yet
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PROPHASE
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PROPHASE
nuclear envelope disappears
nucleolus disappears
chromosomes become visible
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PROPHASE
Centrioles
Centrioles migrate form spindle.
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Kinetochore (centromere)
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plant cytokinesis
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Mitosis produces identical offspring (2N---2N)
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Why some cells stop mitosisdifferentiation

• Muscle cells
• Nerve cells
• Critical functions might be disrupted
• Adaptations to this condition

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Importance???

• Growth
• Replacement
• Cancer
• Regeneration of

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Cancer?

• Unregulated mitosis
• Benign
• Malignant/ metastasis
• How does it begin?

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Normal cycle controls

• Internal signals
• External signals
• growth factors
• fibronectin,etc
• carcinogens
• Apoptosis
• Immune functions
• And

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Cell immortilization!!

• Hayflick limit??
• Hela cells
• Contact inhibition
• Increased telomerase activity
• immortalization!

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Immortalization???

• If you replaced
• Why not??look at your shoestrings?
• Telomerase telomeres ?
• Recently
• Implications???

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Mitosis quiz

• Use two words to describe the importance of
  mitosis
• Draw and label the cell cycleinclude G1, S, G2,
  M and cytokinesiswhat happens at each stage?
• Why might telomerase be important?
• What disease is associated with mitosis?
• Are all organisms limited to 50 mitotic divisions?

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Name stage of mitosis
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Name stage of mitosis
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Name stage of mitosis
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Name stage of mitosis
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Name stage of mitosis
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Name stage of mitosis
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Name stage of mitosis
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Name stage of mitosis
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These are bacteria

• Watch the clip
• What kind of reproduction is shown here?
• What advantage does this confer on the organism?