mitosis

• Why do we need new cells?

  • To repair damaged tissue,eg. wounded skin.
  • To grow, eg. make new/more bones, muscles etc.
  • To replace worn out tissue or cells,eg. blood cells, skin etc.
• The stages of mitosis:

  
• Mitosis-the process by which 1 cell divides to form 2 cells called daughter cells, each identical to the parent cell.
• Interphase-the cell spends most of its life in this phase. The DNA in chromosomes copies itself ready for mitosis. The cell grows.
• • Most living things start life as a single cell, but contain billions and billions of cells as they grow.
  • This is due to cell division.
  • During cell division, a parent cell divides into two genetically identical daughter cells. 
  • These daughter cells then divide in two, and so on.
• Mitosis stages:

  1. Before a cell can divide, it grows and increases the number of sub-cellular structures,eg. ribosomes and mitochondria.
  2. The DNA replicates to form two copies of each chromosome.
  3. One set of chromosomes is pulled to each end of the nucleus and the nucleus divides.
  4. Finally, the cytoplasm and cell membranes divide to form two identical cells.