Stem Cells Flashcards
Define stem cell
A unspecialised cell that can divide and differentiate to become different types of cell for the whole of the organism’s life time
Define “totipotent”
The ability of a cell to differentiate into all specialised cell types
Including extra embryonic cells (e.g placenta)
Where can totipotent stem cells be found?
Very early mammalian embryos
Define “pluripotent”
The ability of a cell to differentiate into all specialised cell types within an organism but not extra embryonic cells
Define “multipotent”
The ability of a cell to differentiate into a few types of specialised cell
Where can multipotent stem cells be found?
Bone marrow
Define “differentiation”
The process by which a cell becomes specialised
How do cells become specialised in animals?
- All cells contain all of an organism’s DNA
- Conditions within cells control which genes are expressed (transcribed and translated) into proteins
- Changes internal environment of cell
- Affects transcription of other genes
- Cells become specialised - this is irreversible
What can embryonic stem cells be used for?
- Repair
- Transplantation
What type of injuries could embryonic stem cells be used to treat?
- Spinal cord injuries
- Heart disease and damage caused by heart attacks
What are the two ways immune system problems with stem cells can be overcome?
- Immunosuppressant drugs
- Tissue typing
How can embryonic stem cells be obtained? 4
- Embryos created in lab using IVF
- Egg cells fertilised by sperm outside the womb
- Once embryos = 4 - 5 days, stem cells removed from them
- Rest of embryo destroyed
What can adult stem cells treat?
- Leukaemia (WBCs and RBCs)
- Burns (skin cells)
How are adult stem cells obtained?
- Relatively simple operation with little risk but discomfort
- Donor anaesthetised, needle inserted into bone centre
- Small quantity of bone marrow is removed
What is the difference between plant and animal cells in terms of stem cells?
Plant cells remain totipotent all their life - differentiated cells can redifferentiate and develop into new plants entirely
How is plant cells always being totipotent useful?
Gardeners regenerate whole plant clones from root, stem and leaf cuttings
What is the main objection to using stem cells?
Many believe embryo destruction is wrong as they believe genetically unique individual formed has a right to life
What 5 things do regulatory bodies do?
- Decide if proposals of research should be allowed
- Licensing and monitoring centres of research e.g stem cell research: avoids unregulated research and ensures researchers are fully trained
- Produces guidelines and codes of practice, ensures all scientists work in a similar manner
- Monitoring developments in scientific research, ensuring guidlines are up to date
- Providing information and advice to government and professionals
What are the advantages of stem cells?
- Saves lives
- Improves quality of life
- Prevents suffering
How could the objection to embryonic stem cells be worked around? And what is the problem with this solution?
- Use unfertilised eggs triggered to divide
- But adult stem cells not pluripotent
What are the risks of using stem cell treatment?
- Infection from the donor
- Risk of infection from contaminated equipment during the procedure
- Risk of cancer
- Rejection from immune system
- Increased susceptibility to infections due to immunosuppressant drugs
