stem cells

• embryonic

  • can divide into most types of cell
  • therapeutic cloning - embryonic stem cells produced with same genes as patient. no rejection
• adult stem cell

  • can divide into limited number for cells (e.g. bone marrow stem cells can form various blood cells)
• meristem

  • found in plants. can differentiate into any type of plant cell
  • clone rare species to prevent extinction. crops with special features can be clones
• pros - treatment of diseases such as diabetes, dementia and paralysis

  cons - ethical and religious objections. can transfer viruses held within cells