stem cells Flashcards
what is meant by stem cells ?
- undifferentiated cells that can continually divide and become specialised
what is meant by differentiation ?
- the process by which stem cells become specialised
what are the 4 different types of stem cells ?
- totipotent
- pluripotent
- multipotent
- unipotent
totipotent ?
- stem cells that can divide and produce any type of body cell
what happens to totipotent cells during development?
- they translate only part of their DNA, resulting in cell specialisation
where and for how long do totipotent cells occur ?
- occur only for a limited time
- in early mammalian embryos
what is meant by pluripotent cells
?
- stem cells found in embryos
- and can become almost any type of cell
where are pluripotent cells used ?
- used in research
what is the prospect of using pluripotent cells in research ?
- they are used with the prospect of using them to treat human disorders
what are the possible ways that stem cells can be used in medicine ?
- used to regrow damaged cells in humans
- replace burnt skin cells
- beta cells for type 1 diabetics
- neurones in parkinsons disease
what are the non- ethical issues surrounding using pluripotent cells in medicine ?
- sometimes treatment does not work
- stem cells continually divide
out of control to create tumours
what are the ethical issues surrounding using pluripotent cells in medicine ?
- there is a debate whether it is right to make therapeutic clones of the patient to make an embryo to get stem cells to cure a disease and then destroy the embryo
where are multipotent and unipotent stem cells found ?
- in mature mammals
what are multipotent cells ?
- stem cells that can differentiate into a limited number of cells
where can multipotent stem cells be found in ? and what do thy differentiate into ?
- in bone marrow
- differentiate into a number of different blood cells
what are unipotent stem cells ?
- stem cells that can differentiate into 1 type of cell
- muscle cells will only make more muscle cells etc
source of pluripotent stem cells in mammals ?
- embryos
- up to 16 days after fertilisation
source of multipotent stem cells in mammals ?
- umbilical cord blood
- placenta
what can adult stem cells found in the bone marrow produce/ differentiate into ?
- they can produce different cells to repair those within a particular tissue or organ
which stem cells are the most useful in terms of applications in medicine ?
- pluripotent stem cells
how do doctors get around the ethical issues surrounding the use of pluripotent stem cells in medicine ?
- by using induced pluripotent stem cells (iPS cells)
how do iPS cells overcome the ethical issues of embryonic pluripotent stem cells ?
- they can be produced from adult somatic cells of an adult who gave consent
- using appropriate protein transcription factors
step 1 of obtaining iPS cells ?
- created from adult unipotent cells
- cells can be from almost any body cells
- they are then altered in a lab to return them to a state of pluripotency
how are somatic cells returned to the state of pluripotency ?
- genes that were switched off to make the cell specialised must be switched back on
- this is done suing transcription factors
what are the advantages of iPS cells ?
- they are very similar to embryonic pluripotent stem cells
- do not cause the destruction of an embryo
- adult can give permission for somatic cells to be obtained
-they are shown to have self renewal properties
what is meant in iPS cells having self renewal properties ?
- they can divide indefinitely to give limitless supplies
