Cellular differentiation, stem cells & modern medicine - 26 Flashcards
How do cells change during development
They become more specialised and less flexible
Describe the development of an embryo cell
Begins as a number of naïve Totipotent cell
Progressive restriction of cells terminally differentiated and can only give rise to one cell
What are Totipotent cell
Cells that have the capacity to do/become anything
Describe pluripotent cells
Embryo stem cells give rise to all cell types
What are the exceptions to this
Stem cells, germ cells (egg and sperm)
Why can we use embryotic cells to produce offspring but not other body cells
All differentiated cells contain all DNA required to build an entire new organism but most stop developing before this occurs.
What are embryotic stem cells (ESC)
‘harvested’ from inner cell of future embryo. Genetically identical to embryo donor. Pluripotent (regenerate to any cell type given right conditions)
What are induced pluripotent stem cells (iPS)
Made by reprogramming adult skin cells (reversing them to act like embryo cells). Genetically identical to source. Pluripotent (regenerate to any cell type)
Describe adult (tissue) stem cells
Can be divided without limit. Multipotent (undifferentiated) Can divide into 2 daughter cells that can be a mix of stem cells and functional cells
Describe umbilical cord stem cells
Can be banked. Help treat blood diseases (leukaemia). Multipotent - immature and less restricted than adult tissue.
Describe why stem cells are important
Stem cells are important for tissues that need constant renewal (skin and blood).
Where are blood stem cells stored and called
In bone marrow - Haematopoietic stem cells
Describe multipotent cells
Often only give rise to one or a few cell types (bone marrow cells)
What is gene therapy
Alter the genetic code of an individuals cells. Correcting single gene disorders.
How does gene therapy work
Inserting a normal allele into cells of affected tissue (delivered on a virus) CRISPR may also be used.
