| Stem cells originate from various sources in mammals: | - Embryo
- Umbilical Cord
- Placenta
- Adult Stem Cells
- (AIPS) (adult induces pluripotent stem cells) - NOW THEY USE THIS AND THEN GENETICALLY MODIFY IT |
| Types | - Totipotent – can differentiate into any of the 200 types of body cell (early embryo)
- Some cells are multipotent – e.g. cells in the bone marrow can become white or red blood cells (some adult stem cells/umbilical cord stem cells)
- Pluripotent – can differentiate into many types (later embryonic cells)
- Unipotent – one type of cell (Adult cells) |
| Why do only some cells retain totipotency ? | - As an organism develops the cell DIFFERENTIATES
- This means that some genes are switched on and some are switched off
- The more specialised a cell is the less ability it has to become other cells |
| 'Switched off' = | Stopping translation and transcription |
| 'Switched on' = | Initiating translation and transcription |
| Gene expression | - Controlling protein synthesis |
| The ethical debate FOR | - Any 2 uses : Paralysis, Type 1 diabetes, parkinsons etc
- Embryos are discarded from IVF clinics AIPS are available |
| The ethical debate AGAINST | - Rejection from patient
- Destroying Life
- Can become cancerous
- Cost of research |
| Pluripotent cells in treating human disorders | There are many possible uses of pluripotent cells. The cells can be used to regrow tissues that have been damaged in some way, either by accident (e.g., skin grafts for serious burn damage) or as a result of disease (e.g., neuro-degenerative diseases, such as Parkinson's disease). |
| B cells of the pancreas | Type 1 diabetes |
| Skin cells | Burns and wounds |
