Stem cells Flashcards
What is cell differentiation ?
Cell differentiation is the process where a cell develops new sub-cellular structures (structures inside a cell) to let it perform a specific function. When this happens, the cell becomes specialised.
When does cell differentiation start in animals?
From the embryo
Organisms start with one cell then divide to make the embryo that differentiate to produce cells that can produce all of the body’s function
Cell differentiation in plants
Many plant cells keep their ability to differentiate throughout their life.
This way they are always able to create new tissue
Cell differentiation in adults
It rare in mature adults. Their cells usually divide in two in order to replace or repair cells.
What are stem cells?
Stem cells are undifferentiated cells that have not yet specialised to perform a specific function. They can create more stem cells or differentiate (become a different type of body cell) to perform another function. They can divide by mitosis to form more cells.
Where are stem cell found?
Bone marrows to repair or replace dying cells, (only blood cells)
embryos to produce all the cell types
And plant meristems allowing them plant to grow forever
Stem cells are used in cloning. Why must we use stem cells, rather than normal cells, to clone an animal?
Stem cells are undifferentiated cells, meaning they differentiate into any kind of cell.
By using a stem cell, we can use cloning techniques, such as replacing the stem cell’s genome, to ensure that the entire cloned animal contains only the desired DNA.
Meristems
Produce unspecialised cells that are able to divide and form any cell type in the plant - they act like embroyonic stem cells. But unlike human stem cells, these can divde and differnetiate to generate any type of cell for as long as the plant lives.
For example palisade cell or root hair cell
Where are stem cells in adults found?
In the bone marrow
Problems of using embroynic cells
Limited supply and ethical issues
Patient immune system may reject because identifies them as a forgein
How do you prevent rejection
You can use adult stem cells taken from the patient so there will no rejection but can only differentiate into blood cells
Steps of stem cell treatment
Extract embryonic stem cells from early embryos.
Grow them in a laboratory.
Stimulate them to differentiate into whichever type of specialised cell that we want.
Give them to the patient to replace their faulty cells.
