Cell Division

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Cell Division
What is the purpose of cell division?
Somatic Cells

• Increase the number of cells in a tissue/organism
• Replace cells that are removed from a tissue

Germ Cells

• Produce gametes for sexual reproduction

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Cell Division in Somatic Cells
What needs to happen to somatic cells during
division?

• Make enough of the various cellular components
  for two cells
• Divide the components equally between the two new
  
• (daughter) cells
• Involves karyokinesis (mitosis) and cytokinesis

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Cell Division in Somatic Cells
DNA Synthesis
Gap/Growth Phase 2
Gap/Growth Phase 1
Cytokinesis
Karyokinesis
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Timing of Cell Cycle
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Timing of Cell Cycle
Why?
Lets back up and look at interphase.
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Cell in Interphase
A time for cell growth and DNA synthesis
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DNA Unwound and Unbound
The DNA must be available for DNA Polymerase for
replication, but image the tangle if we tried to
divide it up in this form.
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Timing of Cell Cycle
Why?
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Packaged to Move
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Overview of Cellular DNA
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Mitosis
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Chromosomes align equatorially
Prophase
Interphase
Metaphase
Mitosis
Anaphase
Telophase
Telophase
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Chromosome Structure
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Centromere Structure of Metaphase Chromosome
Centromere
Sister Chromatids
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Separating Sister Chromatids Anaphase
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Chromosome Structure
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Prophase
Interphase
Metaphase
Mitosis
Anaphase
Nonsister chromatids separate
Telophase
Telophase
Cytokinesis divides the cytoplasm to give two
cells
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