cell division and stem cells

• Stem cells

  Undifferentiated cells that can differentiate into any other type of cell
• Sources of stem cells

  • Embryonic tissue
  • Adult stem cells that occur in some tissue
• Stem cells

  • Can be used to replace damaged or diseased tissue
  • Have many medical applications
• Using your own stem cells

  • No rejection
  • No need to find a donor
  • No need for tissue typing
  • Avoids the use of embryonic stem cells which raises particular ethical issues
• Mitosis

  A type of cell division which organisms use for growth, repair of damaged cells, and replacement of old cells
• Mitosis

  • Produces 2 daughter cells
  • Each daughter cell is genetically identical
  • Has the same number of chromosomes as the mother cell
• Meiosis

  The type of cell division which only occurs for formation of sex cells (gametes) like eggs and sperm for sexual reproduction
• Genes

  Code for characteristics
• Chromosomes

  • Linear arrangements of genes
  • Come in pairs, one from each parent
• Allele

  A different version of the same gene
• Allele

  • Brown, blue, green or hazel (for eye colour)
• Cell division (Mitosis)

  1. Mother cell has 4 chromosomes (2 pairs)

  2. DNA replicates and one copy of each chromosome goes into each cell

  3. 4 new cells are formed

  4. Each cell has half the chromosomes the mother cell has - they are haploid

  5. Cells are not genetically identical to the mother cell
• Cancer is the result of uncontrolled mitosis