mitosis

• Mitosis is a type of nuclear division that ensures each daughter cell receives the same number of chromosomes as the parent cell
• It is one cellular division occurring within somatic (body) cells and involves a diploid parent cell dividing into 2 genetically identical diploid daughter cells.
• Multicellular organisms begin life as a single zygote that undergoes mitosis and grows into an embryo and then foetus. As cells differentiate and specialise they form tissues and some of these cells lose the ability to divide by mitosis.
• Important role for:

   growth of multicellular organisms

   maintenance and repair of damaged cells and tissues in multicellular organisms

   genetic stability to ensure the precise and equal distribution of chromosomes to ensure each cell has the same genetic information
• prophase

  • chromosomes condense (shorten and thicken) and become visible
  • nuclear membrane breaks down
  • Centrioles move to opposite endsof the cell and form spindle fibres
• metaphase

  • spindle fibres attach to the centromeres of chromosomes
  • chromosomes align along the equator in the middle of the cell
• anaphase

  • spindle fibres contract, splitting the centromeres and separating the sister chromatids
  • separated chromosomes arepulled to opposite ends of thecell
• telophase

  • nuclear membrane reforms around the 2 sets of chromosomes forming 2 nuclei
  • spindle fibres break down and disappear
  • chromosomes become longer and thinner
• cytokinesis

  Cytokinesis is the division of the cytoplasm. As the cytoplasm divides it and identicalseparates the two nuclei and other organelles into two complete andidentical daughter cells,