6.5 Stem Cells Flashcards
Why do stem cells activity need to be controlled
Too slow division and tissues are not effectively replaced then it causes ageing
If it too fast than this could be a tumour and cause cancer
What does potency mean and what are the three potencies
Difference between them?
Potency for a stem cell is the ability to differentiate into DIFFERENT types of cells
Totipotent : can inti any type of cell, and are embryonic stem cells. These can differentiate into extra embryonic tissues aswell such as the umbilical cord
Pluripotent : can form any tissue type but not WHOLE ORGANISMS. Present in early embryos and are organ of the different type of tissues within an organism
Multipotent: these stem cells can only form a range of cells within a certain type of tissue, such as bone marrow which can differentiate into red and white blood cells.
More in embryonic stem cells
- when are cells totipotent and when are they pluripotent
- what is this called
- present at early stage from zygote and first few division creating 8 - 16 cells are totipotent
- after 7 days the amount of cells are now a blastocyst and the cells are now pluripotent .
- they remain pluripotent until birth
What about adult stem cells , what potency and what research?
- adult stem cells from birth till end of life found in specific places that being multipotent can only differentiate into a select amount of cells in that tissue
- however some research shows they can be artificially made pluripotent again
What about stem cells in extra embryonic tissues like umbilical cord?
What advantages to keeping these
These are also a source of stem cells and the advantage to this is that there is no need for invasive surgery, if these cells are kept they can be used potentially one day in the future.
Another advantage is that as the cells came from that organism, they won’t be REJECTED!
Pluripotent too!
Where are plant stem cells found? (3 )
What cells are made in third one
Importsnt about plant stem cells?
Meristem tissue which are in the root tip and shoot tips of the plants, wherever there is growth
- also found in between phloem and xylem and this is called vascular cambium,
PLANT STEM CELLS STAY PLURIPORTENT WHOLE LIFE AND WILL GROW FROK WHERE THEY FOUND
- cells here become cells needed for phloem (companion, normal and sieve tube elements ) and xylem (dead )
What is unique about plant cells
Once differentiated?
They remain pluripotent forever and can divide into ANY type of tissue (just not full organism remember) whenever such that if one part taken off it can grow there again.
However again once differentiated they can’t divide, this because of cell wall
What could stem cells be hsed in the future for
Heart disease - fix heart muscle
Type 1 diabetes - makes insulin
Parkinson’s - creates the dopamine creating cells again
Alzheimer’s = brain cells no longer destroyed , regrow
Birth defects, spinal injuries etc
Where are stem cells being used already
1) to treat burned skin victims , quicker than grafts from own body
2) to do drug testing on stem cell colonies instead of human
3) to discover more about biological life
What are some ethical considerations
- ethical , destruction of life when he can’t consent, intrinsic value for life
- religious ethics too
- murder
- life begins at conception
- who has ownership of life?
How are some ways have tried to avoid ethical considerations
1) use of extra embryonic tissues like umbilical cord
- however this is pluripotent max not multipotent like embryonic
2) use of adult
- don’t divide as well + totipotent + have higher chance of mutations
3) use of INDUCED PLURIPOTENT STEM CELLS
What are iSPCs
Induced pluripotent stem cells, where adult cells have been genetically modified to act like embryonic stem cells
How are cambium meristems differentiated again
Blood marrow?
Xylem , phloem sieve tube elements and companion
Red and white blood cell = erythrocytes + neutrophils
Why stem cell treatment could be better than drug
This is short term and side effects
As stem cell is regenerative this is long term solution with fewer side effects
