Stem cells (1.2.3)

• Embryonic stem cells ● Form when an egg and sperm cell fuse to form a zygote

  ● They can differentiate into any type of cell in the body

  ● Scientists can clone these cells (though culturing them) and direct them to differentiate into almost any cell in the body

  ● These could potentially be used to replace insulin-producing cells in those suffering from diabetes, new neural cells for diseases such as Alzheimer’s, or nerve cells for those paralysed with spinal cord injuries
• Adult stem cells ● If found in bone marrow they can form many types of cells including blood cells
• Meristems in plants ● Found in root and shoot tips ● They can differentiate into any type of plant, and have this ability throughout the life of the plant ● They can be used to make clones of the plant- this may be necessary if the parent plant has certain desirable features (such as disease resistance), for research or to save a rare plant from extinction
• Benefits of research with stem cells

  Can be used to replace damaged or diseased body parts.

  Unwanted embryos from fertility clinics could be used as they would otherwise be discarded

  Research into the process of differentiation.
• Problems with research with stem cells

  • We do not completely understand the process of differentiation, so it is hard to control stem cells to form the cells we desire.
  • People may have religious or ethical objections as it is seen as interference with the natural process of reproduction
  • If the growing stem cells are contaminated with a virus, an infection can be transferred to the individual
  • Money and time could be better spent into other areas of medicine.