Stem cells Flashcards
What are stem cells?
Unspecialised cells that can develop into other types of cells
What happens when stem cells divide?
They become new cells and become specialised
Where are stem cells found?
In the embryo
In some adult tissue
What are totipotent cells?
Cells that can mature into any type of body cells.
They are present in mammals in the first few cell divisions of an embryo.
What are pluripotent cells?
Cells that can still specialise into any cell in the body but lose the ability to become cells that make up the placenta
Name the stem cells that are present in an adult mammal
Multipotent
Unipotent
What are multipotent cells?
Cells that are able to differentiate into a few different types of cell
What are unipotent cells?
Cells that can only differentiate into one type of cell
Why can stem cells only become specialised during their development?
They only transcribe and translate part of their DNA
Explain the process of how stem cells become specialised
- Stem cells all contain the same genes but during development not all of them are transcribed and translated.
- Some genes are expressed and some are switched off
- mRNA is only transcribed from specific genes
- the mRNA from these genes is then translated into proteins
- these proteins determine the cell structure and control cell processes
- changes to the cell produced by these proteins cause the cell to become specialised. These changes are difficult to reverse
What are cardiomyocytes?
Heart muscle cells that make up a lot of the tissue in our hearts
It is though that cardiomyocytes can’t what?
Divide to replicate themselves
What do some scientists think about cardiomyocytes?
They think that old or damaged cardiomyocytes can be replaces by new cardiomyocytes derived from a small supply of unipotent stem cells of the heart
What treatments can be given using stem cells?
- bone marrow treatments to treat leukaemia
- can be used to replicate damaged nerve tissue in spinal cord injuries
- replaced damaged heart tissue caused by heart attacks
- grow whole bladders to replace diseased ones
- donated windpipes can be stripped down to their simple collagen structure and then covered with tissue generated by stem cells
- organs can be grown
What are the benefits of using stem cells in medical treatment?
To save lives
Improve the quality of life
What are adult stem cells?
Cells that are obtained from the body tissues of an adult
How are adult stem cells obtained?
In a relatively simple operate that has very little risk but can cause a lot of discomfort
Why aren’t adult stem cells as flexible as embryonic stem cells?
They can only specialise into a limited range of cells
What type of cells are adult stem cells?
Multipotent
What are embryonic stem cells?
Cells obtained from embryos at an early stage of development
How are embryonic stem cells obtained?
Embryos are created in labs using IVF.
Egg cells are fertilised by sperm outside the womb.
Once the embryos are approximately 4-5 days old stem cells are removed from them and the rest of the embryo is destroyed
Why are embryonic stem cells good?
They can divide an unlimited number of times and develop into all types of body cells
Why are embryonic stem cells bad?
Due to the ethical issues surrounding embryonic stem cell use
What type of cells are embryonic stem cells?
Pluripotent
What are induced pluripotent stem cells?
Cells that are created by scientists in the lab. The process involves ‘reprogramming’ adult body cells so that they become pluripotent.
Explain the process of making induced pluripotent stem cells
- the adult stem cells are made to express a series of transcription factors that are normally associated with pluripotent stem cells.
- transcription factors can be introduced to the adult cells by infecting them with a specially modified virus. The virus has the genes coding for the transcription factors within its DNA.
- when the virus infects the adult cells, these genes are passed into the adult’s cells DNA meaning that the cell is able to produce the transcription factors
What are induced pluripotent stem cells useful for?
Research and medicine in the future
