6.5: Stem Cells Flashcards
What is differentiation?
The process of a cell becomign specialised
What do all cells in eukaryotes being as?
Undifferentiated cells, or stem cells
What is the function of stem cells?
They are the source of new cells necessary for growth, development and tissue repair.
Why are stem cells necessary?
When stem cells become specialised, they lose the ability to divide. So a constant supply is needed
What happens if stem cells divide too slowly?
The organism begins to age
What happens if stem cells divide too quickly?
They form tumours, leading to the development of cancer
What is potency?
A stem’s ability to differentiate
What does totipotent mean?
Can differentiate into any type of cell, and can eventually produce a whole organism
What does pluripotent mean?
Can differentiate and form all tissue types, but not whole organisms
What does multipotent mean?
Stem cells that can only form a range of cells within a certain type of tissue
List the order of potency, from most potent to least.
Totipotent, Pluripotent, Multipotent
Which stem cells produce erythrocytes?
Stem cells in the bone marrow
Which stem cells produce neutrophils?
Stem cells in the bone marrow
State the sources of animal stem cells.
Embryonic stem cells, and Tissue (adult) stem cells (in bone marrow and umbilical cord)
What potency are embryonic stem cells?
Initally totipotent, but after a week the cells become pluripotent
What potency are tissue stem cells?
Multipotent
Where are plant stem cells found?
In meristematic tissue. Meristem and apical meristem, and vascular cambium
What potency are meristem stem cells?
Pluripotent.
List some uses of stem cells.
Treatment of burns, drug trials, developmental biology, treating Parkinson’s Disease.
Explain the ethical issues regarding the use of embryonic stem cells.
-Removal of stem cells from embryos normally results in the destruction of the embryo.
-There are religious and moral objections to this, as many people believe life begins at conception, and destruction of an embryo is murder.
-Embryos have no rights.
-Embryos cannot give informed consent
Explain the ethical issues regarding the use of adult stem cells.
-Less contraversial,
-The procedure is painful
-Donor gives informed consen
