Stem Cells Flashcards
What are the 4 types of stem cell?
totipotent
pluripotent
multipotent
unipotent
What is differentiation?
the process by which stem cells become specialised
What are stem cells?
undifferentiated cells which can continually divide and specialise to become different types of cells
What are totipotent stem cells?
stem cells that can divide and produce any type of body cells
Where can totipotent stem cells be found?
zygotes
What results in totipotent stem cells becoming specialised?
some genes are expressed, whilst others are not
What are pluripotent stem cells?
a type of embryonic stem cell that can divide to form ALMOST any type of cell
What are pluripotent stem cells used for?
research into treating human disorders
What are some potential applications of pluripotent stem cells?
- beta cells that produce insulin: diabetes
- neurones: Parkinson’s
- treating burns
What are some issues with pluripotent stem cells?
- can continually divide to create tumours
- ethical issues: therapeutic cloning (making a zygote), destroying an embryo
What are multipotent stem cells?
can divide to form a limited number of cell types
Where can multipotent and unipotent stem cells be found?
bone marrow
umbilical cord
placenta
What are unipotent stem cells?
can only differentiate into one type of cell
What cells can the stem cells found in bone marrow differentiate into?
the different types of blood cell
How can ethical issues of using pluripotent stem cells be overcome?
induced pluripotent stem cells (iPS cells)
How are iPS cells produced?
- take somatic (body) cells from an adult
- use appropriate transcription factors to manipulate the DNA.
- If all genes are ‘switched on’ the cell is no longer specialised
What is it called when all the genes are ‘turned on’?
returning to state of pluripotency
What are the advantages of iPS cells?
- no ethical issues
- can divide indefinitely
- show self-renewal properties
Where can stem cells be found in mammals?
- embryos
- the placenta
- the umbilical cord
- adult tissues
What is one piece of evidence that shows all cells contain all genes, but some are turned off?
iPS - unipotent/somatic cells can be altered to act like pluripotent cells and produce the proteins of an embryonic stem cell
What are 3 ways pluripotent cells can be used to treat human disorders?
- skin grafts for burns
- blood cells for leukaemia
- bone cells for osteoporosis
What processes are regulated in order to control which genes are expressed?
transcription and translation
