Mitosis

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Mitosis

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

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Why more cells?

• Populations of single-cell critters
• Multicellularity?
• We all start out as a single cell?
• The zygote
• become/remain multicellular

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Binary FissionMonera
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Binary Fission..DNA duplicateswhy?
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DNA separates new cell wall divides cell in two
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2 new cellsidentical?
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Binary Fission
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quiz

• What happens to the size of bacteria after binary
  fission?
• What has to happen before fission occurs?
• What benefit(s) do bacteria derive from binary
  fission (as opposed to sexual reproduction)?

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Eukaryotic cells??

• The nucleus?
• Nuclear membrane
• Chromosomesnot chromosome?
• All that stuff in the cytoplasm?

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Eukaryotic cell cycle

• Cell is born
• Duplicates DNA??
• Grows tosize?
• Prepares to divide
• Dividesmitosis

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Control of mitosisCYCLIN
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The nuclelus must first divide before the cell can

• Why?
• How?
• How much time of the cell cycle/life can be spent
  in mitosis?

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Chromosomes duplicate
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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?