mitosis

• Mitosis

  a type of cell division giving rise to genetically idnetical cells in which the chromosome number is maintained
• 2 Daugther cells

  • identical to parent cell
  • idnetical to each other
  • same chromosomes
  • same genes
  • diploid(2n)
• Prophase 


  • Chromatin condenses by supercoiling to become 2 sister chromatids held together at the centromeren
  • Nucleolus gradually disappears
  • nuclear envelope breaks down
  • in animals, the centrosome (absent in plants) divides and the 2 centrioles replicated to form 2 centrosomes
• Metaphase


  • 2 centrosomes move to oppostie ends of the cell
  • microtubles of the cytoplasm strat to form into a spindle, radiating out from the centrioles
  • each pair of sister chromatids is attached to a microtubule of the spindle and is arranged at the equator of the spindle
• Anaphase


  • Centromeres separate
  • Spindle fibres shorten
  • Sister chromatids are pulled by centromeres to opposite poles
  • once separated, the sister chromatids are referred to as chromosomes
• Telophase


  • Nuclear envelope reforms around both groups of chromosomes at opposite ends of the cell
  • Chromosomes 'decondense' by uncoiling, becoming chromatin again
  • Nucleolus reforms in each nucleus
  • cleavage furrow