What are Stem cells?
An undifferentiated cell that can divide to reproduce more undifferentiated cells which can differentiate into other types of cells
Where in the human adult body or stem cells found?
Stem cells and bone marrow differentiate to form cells found in our blood.
Define differentiate
The process in which an unspecialised cell becomes a more specialised cell type.
What happens once the bone marriage transplant is complete?
The cells divide to create new bone marrow and differentiate to make new blood cells
Describe the therapeutic cloning
. Embryo is produced with the same genetics as patient.
. Stem cells from embryo can be transplanted without being rejected by patient immune system.
. These stem cells can then differentiate to replace cells that have stopped working correctly.
. E.g. Diabetes or paralysis.
what are the risks of the bone marrow transplant?
. Donor has to be compatible with the patient or white blood cells produced by the donated bone marrow will start attacking the body
. A virus could be passed on through the transplant from the donor to the patient.
what are the problems with therapeutic cloning?
Some people are against it for religious and ethical reasons
Define a specialised cell
A cell specialised to perform a specific function
What are muscle cells specialised for?
To contract
How are muscles specialised?
Long tubes and lots of mitochondria to provide energy
How are nerve cells specialised and what for?
- Nerve cells are long, in order to carry electrical signals around the body and end in branches that connect with muscles, glands or other nerve cells.
- specialised to send signals called impulses
What and how are sperm cells specialised/for?
- to carry the male DNA to the female DNA
- long flexible tail allows them to swim to the egg cell
- large number of mitochondria in the middle section to provide energy
- the head carries enzymes to help the sperm break through the membrane of the egg
How are plant root hair cells specialised and what for?
- adapted to absorb water and mineral ions
- long and thin = large surface area
- large surface area = easier to absorb water and nutrients
What and how are xylem cells specialised/for?
- to transport water up the plant
- hollow tubes reinforced with linen for strength
What and how are phloem cells specialised/for?
- to transport sugar up and down the plant
- elongated cells
- contains pores in their end walls so that sugar molecules can pass from one cell to the next
