The Cell Cycle: Mitosis and Meiosis

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The Cell Cycle Mitosis and Meiosis

• Raven, P and G. Johnson 1992 Biology. Third
  Edition. United States Mosby Yearbook
  Publishing.
• Raven, P and G. Johnson 1992 Biology
  Principles and Explorations. Third Edition.
  United States Holt, Rhinehart and Winston.

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The Cell Cycle

• Cell Growth (G1)
• Synthesis (S)
• Cell Growth (G2)
• Mitosis
• Cytokinesis

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Growth Phase 1 (G1)

• This checkpoint makes the key decision of whether
  the cell will divide (if cell is healthy, large
  enough, conditions are favorable, some proteins
  will stimulate the cell to begin synthesis.
• Cell grows rapidly.
• Cells that are not dividing remain in G1

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Synthesis Phase (S)

• The cells DNA (deoxiribonucleic acid) replicates
  (copied)
• At the end of this phase each chromosome consists
  of two chromatids attached at the centromere

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Second Growth Phase (G2)

• Preparation for the nucleus to divide
• Microtubules are assembled

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Mitosis and Cytokinesis

• Each nucleus ends up with the same number and
  kinds of chromosomes as the original cell
• The process of cell division in which the
  cytoplasm divides is cytokinesis

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• During meiosis I, each duplicate chromsome lines
  up with its partner, homologue to homologue then
  the partners are separated from each other

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• During Meiosis II, the two sister chromatids of
  each chromosome are separated from each other

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