stem cells Flashcards
stem cells defintion
undifferentiated cells tht can continually divide and become specilaised
differentiation
process where stem cells become specialised
how do differentiated cells differ from eachother
produce different proteins (depending on what genes are expressed), only part of DNA of a cell is translated into proteins
totipotent
can differentiate into any type of body cell
found in early embryo
e.g zygote
pluripotent
can differentiate into almost any type of cell (found in embryo but not placenta)
can divide in unlimited numbers, used in medcine
multipotent
can differentiate into a limited number of specialised cells, usually develop into cells of a particular type
found in mature mammals
e.g bone marrow > blood cells
e.g adult stem cells and umbilical cord blood cells
issues of pluripotent stem cells
divide in unlimited numbers, tumour
ethical issues, destruction of an embryo
is it right for humns to be cloned to produce embryos
unipotent
can only differentiate into a single type of cell
derived from multipotent stem cells and made in adult tissue
e.g cardiomyocytes, heart muscle cells that can divide to produce new heart tissue therefore repair damage to heart muscle cells
iPS cell
type of pluripotent cell created form adult unipotent cells
how are iPS cells formed
adult unipotent cells treated with transcription factors to switch on genes that induce pluripotency
advantages of iPS cells
don’t cause embryonic destruction
self-renewal property- divide indefinitely
used in medical treatment instead of embryonic stem cells
self renewal:
the ability to go trough numerous cycles of cell divison while maintaining the undifferentiated state
what do iPS cells show
the fact genes are able to be reactivated shows that adult stem cells retain the same geentic info that was present in embryo
totipotency
cells differentiate from a single fertilised egg
cells such as fertilised eggs which can mature into any body cell are known as totipotent cells
later differentiate and become specilaised
