Mitosis: Cell Division in Eukaryotic Cells

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MitosisCell Division in Eukaryotic Cells

• Ch 10 Section 2

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Introduction Review

• As we know
• Eukaryotic cells are more COMPLEX than
  prokaryotic ones.
• Prokaryotic cells (like bacteria) can
• Make a copy of their DNA and then simply split
  into two cells.
• Eukaryotic cells require additional steps b/c
  their DNA is compacted in a nucleosome.

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The Cell Cycle

• Def Sequence of growth, division, and resting
  that a cell goes through in its life.
• Separated into five (5) phases, that fall under
  two (2) groupings
• Interphase
• Made of 3 phases
• Cell Division
• Made of 2 phases
• Click HERE to see it in action.

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Interphase

• Made up of G1, S and G2.
• DNA is seen as chromatin.
• G1 (AKA first gap phase)
• Rapid cell growth and organelle production.
• Cells are in this phase for 90 of the time.
• S (AKA DNA synthesis)
• DNA is copied to make the sister chromatids.
• G2 (AKA second gap phase)
• Continued growth to prep for division.
• Structures organize themselves for division.

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Cell Division

• Made up of mitosis and cytokinesis.
• Mitosis
• When division of the cells nucleus takes place,
  and two cells start to form.
• MUCH more detail in a second
• Cytokinesis
• When organelles and cytoplasm are divided equally
  between the two new cells.

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The Four Stages of Mitosis

• Prophase
• Chromosomes condense and become visible by a
  light microscope.
• Nuclear membrane breaks down.
• Centrosomes duplicate and move to opposite ends
  of the cell.
• Spindle fibers form.

Prophase
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The Four Stages of Mitosis
Prophase

• Metaphase
• Condensed chromosomes line up in the middle of
  the cell.
• Spindle fibers link the chromatids to opposite
  poles.

Metaphase
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The Four Stages of Mitosis
Metaphase

• Anaphase
• Spindle fibers shorten and pull chromatids apart.

Anaphase
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The Four Stages of Mitosis
Anaphase

• Telophase
• A new nuclear envelope forms around each set of
  chromatids.
• Spindle fibers dissolve.
• Chromosomes uncoil.

Telophase
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Final Phase of Cell Division Cytokinesis

• After mitosis
• Cytoplasm separates to form two new cells.

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Mitosis through a Microscope
Prophase
Anaphase
Metaphase
Telophase
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Summary

• On a ½ sheet of paper
• Summarize what you have learned about the phases
  that a cell goes through as it divides.