KA : 1.4 Cellular Differentiation Flashcards
What is differentiation?
The process where unspecialised cells become altered to perform a special
function.
What is cellular differentiation?
Cellular differentiation is the process by which a cell expresses certain genes to produce protein characteristics for that type of cell which allows the cell to carry out specialised functions.
What is a meristem?
Meristems are regions of unspecialised cells that have the ability to differentiate into any type of cells.
What are the 2 types of meristem and their functions?
Apical meristems are at the tip of re root and shoot. They add length to the plant.
Lateral meristems are found inside the plant at the cambium. They allow the stems to thicken.
What are Stem Cells?
Stem cells are unspecialised cells in animals that can reproduce themselves by repeated mitosis and cell division and can differentiate into specialised cells when required to do so.
Tissue (Adult) Stem Cells
- Involved in maintaining and repairing the body.
- Have narrower differentiation potential than embryonic stem cells as many of their genes are already switched off.
- They are multipotent, meaning they only give rise to a limited range of cells.
Which type of Stem Cells have genes switched off?
Tissue (Adult) Stem Cells have genes switched off whereas Embryonic Stem cells have all genes switched on.
Are Tissue (Adult) Stem Cells multipotent or pluripotent?
Multipotent.
Are Embryonic Stem Cells multipotent or pluripotent?
Pluripotent.
Definition of multipotent?
Multipotent means they can only give rise to the limited range of cells of their particular tissue types.
Definition of pluripotent?
Pluripotent means the cell type is capable of giving rise to several different cell types.
Embryonic Stem Cells
- During early stages of embryo development a blastocyst (cluster of embryonic stem cells) is formed.
- In the SC all genes have the potential to be switched on and are capable of differentiating into any cell type.
Therapeutic uses of Stem Cells
- Skin SC have been used to grow burn patients sheets of new skin (new skin doesn’t have hair follicles or sweat/oil glands)
- SC can be used to repair damage to the cornea and restore sight (only works with patients who have some undamaged limbal cells)
Research value of Stem cells
- Used as model cells to study how diseases develop.
- Used to test drugs.
Ethics and Stem Cells
- Some argue embryo is human life even at earliest stage and that killing them as a result of a procedure is not worth it.
- Some argue life of suffering patients from incurable conditions can be improved.
- Some also argue that they have not developed feature of a human life yet and have no nervous system yet so there is no pain.
