Stem cells Flashcards
Stem cells
cells that have the two key features of having the potential to become different types of body cells and being able to self-renew over many cell cycles as after a few replication cycles they die, Have the ability to divide by mitosis and differentiate into many different tissues, depending on the level of cell potency
Proliferation
cell replication by mitosis
Differentiation
Process by which cells develop the special characteristics that commit them to perform a certain function, changes in gene expression in order to produce specialised characteristics produced in cells, changes the gene expression
Gene expression
Determines characteristic of the cell
Totipotent stem cells
Able to give rise to an entire organism and associated extraembryonic membranes (give rise to any cell including parts of the embryo), taken from cells of the morula
Pluripotent stem cells
Undifferentiated, No tissue specific characteristics such as morphology or gene expression pattern, No specialised function, Capable of giving rise to most tissues of an organism, Embryonic cells which are harvested from the inner cell mass of a 4-6 day old blastocyst, Can only turn into body cells, not embryo cells
Multipotent stem cells
Differentiated to yield specialised cells in the organ they reside in, Have defining morphological features of gene expression patterns, Adult stem cells that can be found in the brain, bone marrow, muscle, skin, pancreas and liver
Placental cord blood stem cells
Types of adult stem cells and are multipotent, Capable of differentiating into all the different blood cells, Can be collected just after the baby is born in case the baby or other family members need them further in life
Cell de-differentiation/cell reprogramming
Turning differentiated cells into stem cells, Non-pluripotent cells can be reprogrammed to act as stem cells, Two methods: Somatic cell nuclear transfer and Induced pluripotent stem cells
Somatic cell nuclear transfer/therapeutic cloning
Body cell/somatic/diploid nucleus from an ordinary body cell is added to the remaining egg cytoplasm without its nucleus, Cell becomes re-programmed in the egg environment and begins to develop into an embryo, How dolly the sheep was made
Induced pluripotent stem cells
Reprogramming your own adult cells, Less of an ethical problem as you are using your own cells, Less likely to reject the cells as they have the same cell identity markers, Goal directed and hypothesis driven
Cell culture
Growing cells in a lab, stem cells attach, divide and spread over the surface of the dish
iPSC’s
Differentiated cells that are reprogrammed back into pluripotent cells
What can scientists do with pluripotent stem cell cultures
can remain undifferentiated under the right conditions, can be encouraged to form specific types of differentiated cells
How can we use stem cells
Understanding biology of diseases, testing drugs and cell based therapies/tissue engineering
