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35 Cards in this Set
- Front
- Back
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What are stem cells? |
Unspecialised cells that have not differentiated and so may specialise to become any cell type and can undergo mitosis |
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How do stem cells become specialised through gene expression? |
Genes expressed-->mRNA transcribed and translated into proteins---> proteins modify the cell---> cell becomes specialised for a particular function |
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What happens if a gene is switched off? |
mRNA not transcribed or translated. Proteins not produced |
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What is the hierarchy of stem cells? |
Totipotent--> pluripotent--> blood stem cells or other stem cells |
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What are the 4 types of stem cells? |
Totipotent Pluripotent Multipotent Unipotent |
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What are totipotent stem cells and where are they found? |
These are found in the early embryo and can differentiate into any type of cell |
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What does this mean? |
Zygotes are totipotent, as the zygote divides and matures, its cells develop into slightly more specialised cells called pluripotent stem cells |
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What are pluripotent stem cells and where are they found? |
They are found in embryos and can differentiate into almost any type of cell. Examples include embryonic stem cells and foetal stem cells |
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What are multipotent stem cells and where are they found? |
These are found in adults and can differentiate into a limited number of specialised cells. They usually develop into cells of a certain type. |
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What are unipotent stem cells and where are they found? |
These can only differentiate into a single type of cell. They're derived from multipotent stem cells and are made in adult tissue |
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What can pluripotent cells be used for? |
They can be used to regrow tissues that have been damaged in some way, either by accident, or as a result of disease |
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What are 5 possible future uses of stem cells? |
Spinal cord injuries Heart disease and damaged caused by heart attacks Bladder conditions Respiratory conditions Organ transplants |
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How can they be used for spinal cord injuries? |
Stem cells could be used to replace damaged nerve tissue |
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How can they be used to help with heart disease and damaged caused by heart attacks? |
Stem cells could be used to replace damaged heart tissue |
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How can stem cells be used to help with bladder conditions? |
Stem cells could be used to grow a whole bladder, which is then implanted in patients to replace diseased ones. |
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How can stem cells be used to combat respiratory diseases? |
Donated windpipes can be stripped down to their simple collagen structure and then covered with tissue generated by stem cells. This could then be transplanted into patients |
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How can stem cells be used for organ transplants? |
Organs could be grown from stem cells, to provide new organs for people on donor waiting lists |
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What are cardiomyocytes? |
The heart muscle cells |
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What was a common misconception about cardiomyocytes? |
In mature mammals, people thought they couldn't divide to replicate themselves, so they can't be regenerated |
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Why would this be an issue? |
It would be a major problem if the heart became damaged or if cells became worn out with age |
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What does recent research suggest? |
Our hearts have some regenerative capabilities |
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What do some scientists believe? |
Old or damaged cardiomyocytes can be replaced by new ones derived from a small supply of unipotent stem cells in the heart. |
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What do some scientists think about this process? |
Some think it's constantly occurring, however, there's disagreement on the speed. |
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What are the differences in opinion about the speed of the process? |
Some believe it's really slow and they're never replaced in a lifetime. Others think it occurs more quickly so every cardiomyocyte is replaced several times in a lifetime |
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What does iPS cells stand for? |
Induced pluripotent stem cells |
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What are iPS cells? |
A type of pluripotent cell that are produced from unipotent stem cells, |
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How are iPS cells made from unipotent stem cells? |
Almost any body cell can be used and it is genetically altered in a lab to make them acquire characteristics of embryonic stem cells (pluripotent) |
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How does this occur? |
This is because the adult cells are made to express a series of transcription factors that are normally associated with pluripotent stem cells. |
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What are transcription factors? |
Proteins that control whether or not genes are transcribed |
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What do the transcription factors do? |
They cause the adult body cells to express genes that are associated with pluripotency |
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What's a useful feature of iPS cells? |
They're capable of self renewal |
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What does this mean? |
They can potentially divide infinitely to provide a limitless supply |
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What is a consequence of this? |
They could replace embryonic stem cells in medical research and treatment, overcoming some of the ethical issues surrounding using embryos in stem cell research |
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What are ethical issues associated with obtaining stem cells from embryos using IVF? |
The procedure results in the destruction of the embryo that could become a foetus if placed in the womb. Some people believe life begins at conception |
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When is embryonic stem cell allowed in the UK? |
Under licensed and specified conditions |
