Stem Cells Flashcards
What is a stem cell?
The fertilised egg and sperm cell form a zygote
That cell divides by mitosis to become the embryo
The inner cells are stem cells that differentiate to form specialised cells
What are adult stem cells?
They are undifferentiated cells of an organism that can give rise to more cells of the same type
Bone marrow is a good source
Small number of stem cells maybe in most different tissues in body
How can stem cells be useful?
Stem cells can stay in some tissues and if the cells are injured or diseased they can start to divide to replace damaged cells
When could we use stem cells in humans?
- Some body parts have cells that cannot repair themselves eg spinal nerves. Embryonic Stem cells can be grown to replace damaged nerve cells.
- Diabetics have pancreas cells that don’t work.
- Macular degeneration can cure blindness, embryonic stem cells can be transplanted to replace the diseased cells.
- Heart after damage of heart attack
- Replacing bone cartilage
When do we use stem cells in plants?
Stem cells from meristems can make a clone of parent plants
Important to produce rare plants reliably and safely
Save some species
We can produce large numbers of identical plants for research
Widely used in horticulture eg orchids for sale
Produce mass crop plants with disease resistance eg bananas
What are the problems with stem cells?
Technology is still new so practical risks
Social and ethical issues
What are the social and ethical problems with stem cells?
Embryos come from fertility clinics donated because they won’t be used
The use of potential humans in this way is wrong because the embryo can’t give permission to violate its human right and some religious objection
What are the practical difficulties?
Scientific progress is slow
Expensive
Hard to control
Only been 20 years of trying so not fully understood yet
Fear that stem cells rapid growth may cause cancer and may carry viruses and trigger the immune response
What is the future for stem cells?
Stem cells are found in umbilical cords and amniotic fluids around foetus in womb
This may overcome the ethical problem because of not using the spare embryos
Adult stem cells also avoid this controversy
Therapeutic cloning may help grow new organs
What is the risk of rejection?
If your own umbilical cord is saved to help treat diseases later in life then there is less risk of the body rejecting those stem cells as they are your own
There is more of a risk of rejection in using someone else’s stem cells
