Stem cells

• Embryonic stem cells can turn into any type of cell
• Differentiation is the process in which a cell changes to become specialised to do its job
• Undifferentiated cells, called stem cells, can divide to produce lots more undifferentiated cells. They can differentiate into different types of cell, depending on what instructions they are given
• Stem cells are found in early human embryos.
• Adults also have stem cells, but they are only found in certain places, like bone marrow
• Stem cells from embryos and bone marrow can be grown in a lab to produce clones and made to differentiate into specialised cells touse in medicine or research
• Stem cells may be able to cure many diseases
• Medicine already uses adult stem cells to cure disease. For example, stem cells transferred from the bone marrow of a healthy person can replace faulty blood cells in the patient who receives them
• Embryonic stem cells could also be used to replace faulty cells in sick people - you could make insulin-producing cells for people with diabetes, nerve cells for people paralysed with spinal injuries, and so on
• In a type of cloning, called therapeutic cloning, an embryo could be made to have the same genetic information as the patient. This means that the stem cells produced from it would also contain the same genes and so wouldn't be rejected by the patient's body if used to replace faulty cells.
• In therapeutic cloning, there are risks involved in using stem cells in medicine. For example, stem cells grown in the lab may become contaminated with a virus which could be passed on to the patient and so make them sicker.
• Stem cells can produce identical plants:

  • In plants, stem cells are found in the meristems (parts of the plant where growth occurs)
  • Throughout the plant's entire life, cells in the meristem tissues can differentiate into any type of plant cell.
  • These stem cells can be used to produce clones (identical copies) of whole plants quickly and cheaply.
  • They can be used to grow more plants of rare species (to prevent them being wiped out)
  • Stem cells can also be used to grow crops of identical plants that have desired features for farmers, for example, disease resistance.