stem cells

• differentiation - aquires different sub-cellular structures
• a stem cell is an undifferentiated cell. it's capable at giving rise to many other stem cells.
• animal stem cells include: embryonic stem cell and adult stem cells.
• embryonic stem cells: can differentiate into any type of cell, can be used to treat diseases - can be cloned -> then made to differentiate into a cell type for treatment such as type 1 diabetes, paralysis and heart repair.
• adult stem cells: limited in their uses as they make a small number of different cell types - found in bone marrow
• plant stem cells: found in meristem tissue which contains stem cells. mitosis constantly takes place at the bottom of meristem tissue so the plant continues to grow.
• cons of adult stem cell: has a risk of carrying disease, which can infect the patient receiving them. If the patient receives a stem cell from an unrelated person there's a chance their body will reject them.

  A solution to this is therapeutic cloning. Cells from patient is used to create an embryo, which has the same DNA as the patient so there is no rejection risk.
• other issues of embryo stem cells:

  Ethical: embryos cant give consent - against their human rights.

  -counter argument: most of the embryos used are left over from

  fertility treatments and would otherwise be discared.

  Religious beliefs: shouldn't interfere with the reproduction process at all.