SBI 3U7
Stem Cells
What are stem cells??
Stem cells are cells that have the ability to differentiate into different tissues and organs of an organism
They also divide many times to produce copious quantities of new cells
Ex. In plants, stem cells are found in the roots and therefore have the ability to differentiate into
various tissues (ex. stems, leaves, more roots…etc.)
Stem cells in animals and humans
There are Two Types of stem cells:
1. Embryonic or pluripotent:
Research has lead to the discovery of embryonic or pluripotent stem cells in mice.
Embryonic/pluripotent stem cells have the ability to differentiate into any tissue present in that
organism.
How do we get embryonic stem cells??
Embryonic stem cells must be taken from embryos.
Usually this happens in laboratories that conduct invitro fertilization (IVF).
 Very controversial because it requires the death of an embryo.
 In many countries, this research is not supported due to cultural, religious or political reasons.
Therapeutic uses or Medical Treatment: Scientists have been studying embryonic stem cells
because they have the ability to differentiate into any cell type. Scientists are hopefully looking
forward to this technology to replace damaged cells do to injury or disease. (Ex. Parkinson’s &
Alzheimer’s disease replace lost brain cells, Diabetes replace damaged pancreas cells)
Scientists have been able to regenerate damaged nerve cells in mice with these stem cells.
Possibilities for Non-Therapeutic uses: Embryonic stem cells are used to produce large
quantities of striated muscle fibres or meat for human consumption. Thus, cattle slaughter not required.
Note:
**Stem cells are very difficult to isolate. We cannot isolate them based on appearance but only
behaviour.
**Stem cells will differentiate into specific tissues or organs but will produce stem cells to remain.
(…..Almost like memory cells)
2. Tissue Specific stem cells/ adult stem cells:
These are stem cells that are found in a specific tissue of an organism. These have been used to treat
humans and have been proven to be successful. Ex. Blood stem cells have been introduced into patients
with leukemia to replace damaged bone marrow.
SBI 3U7
Page 13: Read and discuss in groups:
Therapeutic uses of stem cells: Use of stem cells to treat Stargardt’s disease and one other named
condition. (Leukemia)
The ethical implications of Stem Cell Research:
Briefly outline the differences between embryonic, cord blood stem cells and Adult stem cells