BIOLOGY- stem cells

• Stem cell therapy is the use of stem cells to treat or manage diseases, injuries, or other medical conditions.
• Stem cells are able to differentiate into specialised cells
• Embryonic stem cells can differentiate into any type of cells .e.g. skin cells or blood cells
• Adult stem cells (found in bone marrow) can only differentiate into blood cells such as red blood cells or white blood cells
• Stem cells can replace damaged cells to keep us alive but don't form new tissues
• Stem cells divide by mitosis to form more cells
• Plant stem cells are found in meristems
• Undifferentiated plant stem cells differentiate into the cells and tissues the plant needs such as phloem and xylem cells, root hair cells or palisade cells
• Medical Technique:

  1. Extract embryonic stem cells from early embryos
  2. Grow them in a laboratory
  3. Stimulate them to differentiate into whichever type of specialised cell desired
  4. Give to the patient to replace faulty cells
• Stem cells can be used to treat conditions such as Type 1 Diabetes (faulty pancreas cells), paralysis (damaged nerve cells) or sickle cell anaemia (faulty red blood cells)
• Risks of stem cells:

  • Virus transmission~ the embryonic stem cell might have a virus which can infect the patient
  • Tumour development~ the stem cells may divide rapidly and uncontrollably after being transplanted
• Drawbacks:

  • Treatment requires embryonic stem cells which links to ethical issues as the embryos have potential for human life (therefore the embryonic stem cells are often taken from unwanted embryos in fertility clinics) but others also think that curing existing people is more important (ethical objections)
  • There is a limited supply of stem cells
  • Risk of rejection due to different genomes can be off-putting but the patient can be given immunosuppressants to try and prevent this (immunosuppressants also have side effects)