Stem Cells

Question 1

Stem Cells Def.

Answer 1

• Stem cells are undifferentiated that can continually divide and become specialised.
• Become specialised by differentiation

Question 2

4 different types of stem cells.

Answer 2

1.) Totipotent.
2.) Pluripotent.
3.) Multipotent.
4.) Unipotent

Question 3

What are totipotent stem cells? Where are they found?

Answer 3

• Totipotent: can differentiate into ANY type of body cell.
• Only occur for limited time in early mammalian embryos.

Question 4

What are pluripotent stem cells? Where are they found?

Answer 4

• Can differentiate into ALMOST any body cell.
• Found in embryos.

Question 5

What are pluripotent stem cells used in? What are issues/ ethics surrounding this?

Answer 5

• Used in research to treat human dissorders.
• Issues: treatment doesn’t work/ stem cells continually divide and create tumours instead.
• Ethics: making therapeutic clones of humans/ destroying the embryo (as pluripotent stem cells come from embryos.)

() - extra info for clar

Question 6

What are multipotent/ unipotent stem cells? Where are they found?

Answer 6

• Multipotent: differentiate into limited number of cells.
• Unipotent: differentiate into only one type of cell.
• Where: in mature mammals

Question 7

Give the sources of stem cells in mammals.

Answer 7

1.) Early embryo stage: pluripotent/ totipotent
2.) Umbilical cord blood: multi-potent stem cells ie. adult stem cells.
3.) Placenta contains multi-potent stem cells.
4.) Adult stem cells (ie. bone marrow) produce specialised cells to repair those within specific tissue/ organ.

Question 8

Give an example of multipotent stem cells

Answer 8

• Adult stem cells found in bone marrow, can ONLY differentiate into blood cells.

Question 9

What are induced pluripotent cells (iPS cells?) Advantage of this?

Answer 9

• Induced pluripotent cells (iPS cells) can be produced from adult somatic cells using appropriate transcription factors.
• Advantage: overcomes ethical issues w/ embryonic stem cells.

Question 10

What is the process of creating induced pluripotent stem cells (iPS cells?)

Answer 10

• Created from adult unipotent cells.
• Altered in lab to return to state of pluripotency.
• HOW?: genes that were switched off to make cell specialised are switched on using transcription factors.

Question 11

True or False

Adult unipotent stem cells used to form iPS cells are difficult to find.

Answer 11

• False.
• Can be found in almost every body cell.

Question 12

What are advantages of using iPS cells to treat human dissorders over embryonic stem cells?

Answer 12

• Very similar to embryonic pluripotent stem cells.
• Don’t cause destruction of embryo/ adult can give permission.
• Have self-renewal property –> can divide infinitely to give limitless supplies.

Question 13

Give an example of unipotent stem cells

Answer 13

• Caridomyocytes (heart muscle cells.)