38. Stem Cells Flashcards
Which types of cells are totipotent?
Those from the morula
Which types of cells are pluripotent?
Those from the inner mass of the blastocyst
What are the characteristics of adult stem cells?
High capacity of self-renewal into adult life
Unlimited divisions
Unidirectional and irreversible development
Why do stem cells divide slowly?
To avoid risk of mutation or error
Where are stem cells found in adults?
Intestine, in bone marrow
What is the concept of asymmetrical division?
A dividing stem cell will divide into a stem cell and a daughter cell committed to differentiation
When is stem cell division symmetric?
When need to replaced damaged tissue. Need to make up for lost stem cells, not maintain the same number
What are transit amplifying cells?
A daughter cell which has committed to differentiation which will divide rapidly prior to differentiation to increase cell numbers
How is cell renewal controlled?
Integrins, growth factors, molecular signals
How is therapeutic cloning conducted?
Somatic cell nucleus fused with a denucleated egg cell and stimulated to divide
How can pluripotent stem cells be produced?
What are the drawbacks?
Can be induced by switching on certain gene markers with viruses - reprogrammed into embryonic-like state
Genes switched on linked to cancer
How are stem cells used to react Parkinson’s?
ES cells can proliferate extensively and generate dopamine neurons that are dead
