stem cells

• what are stem cells?

  • in humans, located in bone marrow
  • present in human embryos
  • in plants, located in roots and shoots
• embryonic stem cells

  • derived from embryos
  • can differentiate into any cell type
• adult stem cells

  • found in adult tissues
  • have limited ability to differentiate
• what are stem cells?


  undifferentiated cells that can specialise into different types of cells
• where are stem cells in humans?


  • located in the bone marrow
  • present in human embryos
• where are stem cells in plants?


  located in meristem (roots and shoots)
• what is the function of stem cells in embryos?


  embryonic stem cells can replicate themselves and differentiate into many other cell types
• what can embryonic cells treat?


  they can treat conditions such as

  • paralysis
  • diabetes
• what is the function of stem cells in adult bone marrow?

  adult stem cells can differentiate into several cell types to replace dead or damaged tissues
• what is the function of stem cells in plast meristems?


  meristem stem cells retain the ability to differentiate into any type of plant cell throughout their lifespan
• what is therapeutic cloning?


  a cloning method where an embryo is produced with the same genetic makeup as the patient

  the stem cells which originate from the embryo will not be rejected by the patient's immune system
• what are the advatages of cloning plants using meristem stem cells?


  • can prevent rare plants from becoming extinct
  • can rpoduce large numbers of plants with a favourable characteristic
  • can produce identical plants for research
• what issues are associated with the use of embryonic stem cells?


  • many embryonic stem cells are sourced from aborted embryos - some people have an ethical/religous objection
  • if a donor stem cells do not have a similar genetic makeup to the patient, an immune response could be triggered