Stem cells

• Stem cells

  Undifferentiated cell capable of becoming any other type of cell
• 2 types of stem cells

  Embryonic stem cells

  Adult stem cells
• 2 main features of a stem cell

  Divide by mitosis to form more cells

  They can differentiate into different types of specialised cells
• Embryonic stem cells

  Found in the embryo, which is formed when a sperm cell fertilises an egg cell
• Adult stem cells

  Adult stem cells are found and produced in the bone marrow
• Main difference between the stem cells

  Adult stem cells can only differentiate into a narrow range of specialised cells

  Embryonic stem cells can differentiate into any type of cell
• Meristem tissue

  Plant tissues that are continually growing and contain stem cells
• Steps of treatment using stem cells

  Extract embryonic stem cells from early embryos

  Grow the embryonic stem cells in a laboratory

  Stimulate them to differentiate into whichever type of specialised cells is required

  Give them to the patient to replace their faulty cells
• 3 diseases that can be treated with stem cells

  Sickle cell anaemia- replace faulty rbc’s

  Paralysis- replace faulty nerve cells

  Type 1 diabetes- replace faulty pancreatic cells
• Risk of using embryonic stem cells

  Limited supply of embryonic stem cells

  Risk of rejection

  Some people object to the use of stem cells for ethical reasons
• Two risks of using stem cells in medicine

  Stem cells could be infected with a virus

  As stem cells divide quickly, there’s a chance they could divide uncontrollably and turn into a tumour
• Ethical objection for the use of stem cells in medicine

  People argue that embryos shouldn’t be used for experiments since each one is potential human life
• 3 uses of plant stem cells

  Can produce clones of whole plants quickly and cheaply

  Can be used to grow more plants of a rare species

  Can be used to produce clones that have desired features for agriculture