meiosis

• Meiosis


  The type of cell division that produces gametes
• Gametes

  Sex cells such as sperm cells in males and egg cells in females
• Meiosis


  1. Meiosis 1

  2. Meiosis 2
• Meiosis 1


  1. Prophase 1

  2. Metaphase 1

  3. Anaphase 1

  4. Telophase 1
• Meiosis 2


  1. Prophase 2

  2. Metaphase 2

  3. Anaphase 2

  4. Telophase 2
• Prophase 1


  • Diploid cell
  • Chromatin contains two uncoiled spread out sets of chromosomes
  • DNA replicates
  • Chromosomes condense into X-shaped
  • Homologous chromosomes pair up and bind forming a tetrad
  • Crossing over happens, exchanging segments of alleles
• Metaphase 1


  • Homologous chromosomes line up at the equator and attach to spindle fibers from opposite poles
• Anaphase 1


  • Spindle fibers separate the homologous chromosomes in each tetrad and pull them to opposite poles
• Telophase 1


  • One chromosome from each homologous pair at separate poles, each chromosome still consists of sister chromatids
• Meiosis 2

  • DNA does not replicate before it begins
  • Sister chromatids separate and move to opposite poles
• Meiosis begins with a diploid cell
• Meiosis only produces gametes
• Gametes are genetically different haploid cells
• Crossing over results in genetic differences in gametes
• All gametes produced by meiosis are haploid