8.4 Stem Cells Flashcards
What are stem cells?
Cells that are not yet specialised to do any particular function.
What is a zygote?
A type of cell that all human life starts from, which goes through mitosis to increase in number.
Name the 3 embryo layers:
- Ectoderm
- Mesoderm (middle layer)
- Endoderm (inner layer)
What does the ectoderm (outer layer) of an embryo form?
Forms the exoskeleton.
Eg. Brain and spinal cord
What does the mesoderm (middle layer) of an embryo develop into? Give an example:
Develops into organs.
Eg. Kidney
Name the 2 types of stem cells:
- Embryonic
- Adult
What does the term potency refer to?
The number of types of cells a stem cell can become (differentiate in).
What is a blastocyst?
When an embryo becomes a hollow ball, which starts to specialise (differentiate) as it develops layers.
What does the ectoderm (inner layer) of an embryo form? Give an example:
Forms the lining of organs.
Eg. Lungs
Name the 4 types of stem cell potency:
- Totipotent
- Pluripotent
- Multipotent
- Unipotent
What does it mean if a stem cell is totipotent?
When a stem cell can become any cell type or even another embryo.
What does it mean if a stem cell is pluripotent?
When a stem cell can become any of the 3 germ cell layers.
What does it mean if a stem cell is multipotent? Give an example:
It can become multiple types but limited.
Eg. Certain stem cells in bone marrow can become any blood type.
What does it mean if a stem cell is unipotent?
Can only turn into one type of cell but can replicate repeatedly.
What are embryonic stem cells?
Cells from zygote to blastocyst stage, which can replicate indefinitely and become many different types of cell.
What are adult stem cells?
Cells that are present in small numbers in some adult tissues, which can only become certain types of cells and cannot replicate indefinitely,
What is the function of adult stem cells?
To repair and regenerate damaged and aged tissue.
How are stem cells possibly going to be used by scientists in the future?
A great deal of research is underway to utilize stem cells to treat individuals with conditions such as Parkinson’s disease and type 1 diabetes.
What are the advantages of embryonic stem cells?
- Unlimited supply
- Cell division can occur indefinitely
- Can grow into large quantities
- Can become any cell type
What are the advantages of adult stem cells?
Already programed to be a particular cell type and so can be used for specific conditions
What are the advantages of induced pluripotent stem cells?
- Use normal adult cells
- No immune system rejections as cells come from the original patient
Name 3 disadvantages of embryonic stem cells:
- Can’t grow cells of every possible tissue type yet
- Ethical objections
- Potential for uncontrolled cell growth
Name 3 disadvantages of adult stem cells:
- Limit on cell types which they can differentiate into
- Smaller number of cells
- Potential for uncontrolled growth
Name 3 disadvantages of induced pluripotent stem cells:
- Technology not yet fully developed
- Maybe limited in differentiation type
- Potential for uncontrolled growth
