Stem Cells Flashcards
What is a stem cell
Self renewing undifferentiated cell
It has the ability to differentiate into any other specialised cell
What is potency
The ability of stem cells to differentiate into more specialised cell types
What are the 3 types of potency
- Totipotent - undifferentiated stem cells that can differentiate into any cell type found in the embryo
- Pluripotent - undifferentiated embryonic stem cells that can differentiate into any cell type found in the embryo but are not able to differentiate into extra embryonic stem cells
- Multipotent - undifferentiated stem cells that can differentiate into any cell limited range of cell types
Describe a totipotent stem cell
Embryonic stem cells
All genes are switched on - every protein can be produced
Undifferentiated stem cells that can differentiate into any cell type that make up the organism
Example: placenta, umbilicus and amnion
In a dividing state
What tissues do the inner and outer cells of the blastocyst form
Outer - placenta
Inner - form tissue of the developing embryo
What are pluripotent stem cells
E,Byronic stem cells that can divide in unlimited numbers and can develop into most of the body’s cell types but cannot differentiate into the placental tissue, nor umbilicus or amnion
They cannot give rise to extra embryonic cells thus not cells for an entire organism/foetus
Cells are in a dividing state
What are multipotent stem cells
Cells that differentiate into a limited range of cell types
They are not usually in a diving state, divide to replace cells which have been damaged or worn out
What are meristems
Unspecialised cells that have the ability to differentiate into any type of specialised plant cell and therefore an entire plant
Meristems are in a diving state
What is the location of meristems
Lateral meristems - cambrium in the stem
Apical meristems - tips if shoot and root
Compare animal and plant stem cells
Plant maintains a high number of stem cells throughout their lives - animals lose stem cells as they develop
Plants go throughout their life - animals do not
Plant stem cells are found mainly in apical meristems in the short tip and root tip - animal stem cells are found throughout the body
What is the source of embryonic stem cells + ethics
Excessive embryos form IVF
Embryo destroyed, taking away a right to life, embryo cannot give consent
What is the source of pluripotent stem cells
Embryo - taken at the 16 stage cycle from IVF (left longer than totipotent stem cells)
embryo destroyed, taking away a right to life, embryo can’t give consent
What are the uses of multipotent stem cells
Replacing damaged or worn out cells such as making new skin or blood cells
Bone marrow transplants - widely used in treatment of blood cells such as disorder (leukaemia)
State 2 properties if pluripotent stem cells that make them suitable for treating conditions with no cure
The cells divide and are able to differentiate into different types of specialised cells which make up tissue
describe how embryonic cell gives rise to tissues and organs as a foetus develops and how the growth patterns of tissues differ
embryonic cells divide by mitosis to produce genetically identical cells
different genes in each cell are switched off/on
each cell becomes specialised for a particular function
each specialised cell makes a different protein
groups of specialised cells form tissues
groups of different tissues form organs and different organs form organ systems
example: brain and spinal cord from the nervous system
what are the uses of multipotent but also the issues that come with it
replacing damaged or worn-out cells such as making new skin or blood cells
bone marrow transplants - widely used in treatment of blood cell disorders
donor cell antigens recognised as foreign, so immunosuppressive drup treatment required
ethical harvesting bone marrow is painful and risky
ethical: babies can be concieved to provide a bone marrow transplant for sibling (with a condition requiring the transplant)
what is therapeutic cloning
fertilised cell removed - allowed to duplicate to embryo (shows it is viable)
embryonic cells cultured in sterile conditions allows for replication without contamination in with transcription factors - optimum environment
transcription factors lead to switching on/off specific genes
genes produce proteins - cell gives rise to a differenciated cell - tissues and organs for medical treatment
what are some advantages of using embryonic stem cells in therapeutic cloning
limitless self-renewal - generates lots of cells
if obtained from unbilical cord - umbilical cord is detached from infant at birth away - also obtained from miscarriages
totipotency - treates many diseases better quality of life
can be made to trat lots of people therefore cheaper, can produce tissues and organs - organ transplants instead of coming from animals came from humans
what are some disadvantages of using embryonic stem cells in therapeutic cloning
might divide out of control - leads to tumour/cancer
antigens of embryonic cells would be recognised as foreign by patient - patient would have to take immunosuppressive drugs to avoid rejecting the treatment - weakens the immune system making them prone to infections
requires destruction of an embryo so there are many ethical issues - many have the potential to form a life (ethical) + right to life
infections from needles
