Lecture 32: Cloning, Stem Cells and Gene Therapy Flashcards
Cells become more ______ and less ______ during development.
- Specialised
- Felxible
What is the trophectoderm?
- Placenta
Embryo begins as a small number of naive, ________ cells.
- Totipotent
Embryonic stem cells can give rise to all cell types except trophectoderm, these are known as _____ cells.
- Pluripotent
Progressive restriction of cell fate until terminally differentiated, and can only give rise to same type of cell. Except _____ and ______ cells.
- Stem
- Germ
- (Eggs & Sperm)
In Embryonic cells, at the beginning, control genes (myoD) and all other muscle specific genes are turned….
- Off
When myoD proteins in an embryonic cells are turned on, and other muscle specific genes are turned off, it’s getting ready to… (Determination)
- Become a muscle cell
When myoD proteins in an embryonic cells are turned on, and other muscle specific genes are turned on, it’s become a… (Differentiation)
- Muscle cell
Features of stem cells:
- Can divide without limit
- Undifferentiated
- Can divide and maintain their population
The difference between adult stem cells and embryonic stem cells:
- Embryonic stem cells = totipotent and give rise to all types of blood cells
- Adult stem cells, come rom bone marrow and mostly give rise to blood cells
Stem cells are important for tissues such as….
- Blood and skin
Plasticity:
- The ability of stem cells from one adult tissue to generate differentiated cell types of another tissue
Bone marrow also contains mesenchymal stem cells which can give rise to…
- Blood cells and some cartilage cells
Umbilical cord stem cells are often…however are not _______ but are immature…….
- Banked (kept frozen)
- Pluripotent
- Blood stem cells
Induced pluripotent stem (iPS) cells are…
- Made by reprogramming adult cells
Gene therapy is best applied to…and can be achieved using..
- Stem cells
- Because they will keep dividing and pass on corrected gene
- Retroviruses
Early embryo =
Differentiated cell =
Stem cells =
- All or most cell types
- One cell type
- Some cell types and more stem cells
How was Dolly the Sheep cloned?
- Forced donor mammary cells into G0 ‘resting’ phase of the cell cycle
- Delivered pulses of electric current to the egg
- Nuclear genome from nuclear donor
- She’s identical to the mammary cell donor but the mitochondrial genome comes from the egg donor
- No DNA from surrogate mother
Why clone humans?
- Dolly is an example of reproductive humans
- Therapeutic cloning involves the creation of “personalised” embryonic stem cells
- A donor nucleus is transferred into an enucleated zygote as for reproductive cloning
- The embryo is cultured until the blastocyst stage
- Cultured under various conditions to make cell types to order
- iPS cells from patients with genetic disease can also be used to make cells or tissues for drug testing
- Use minilungs for drug testing, so you don’t have to use humans
