Specialised cells

Question 1

What is a stem cell?

Answer 1

Undifferentiated cells that can continually divide and become specialised.

Question 2

What is differentiation?

Answer 2

Process by which stem cells become specialised.

Question 3

Describe totipotent stem cells

Answer 3

Can divide and produce any type of body cell.

Occur only for limited time in early mammalian embryos

Only translate parts of DNA resulting in cell specialisation.

Question 4

Describe pluripotent cells

Answer 4

Found in blastocyst/embryo and can become almost any type of cell.

Used in research to treat human disorders.

Used to regrow damaged tissue.

Sometimes can continually divide —> tumour

~~ethical issues

Question 5

Describe multipotent/unipotent cells

Answer 5

Stem cells found in mature mammals and can divide to form limited number of different cell types.

Unipotent –> only one cell

Question 6

What are some sources of stem cells in mammals?

Answer 6

16 days after fertilisation = pluripotent and can differentiate into any type of cell

Umbilical cord blood contain stem cells which are multipotent like adult stem cells.

Placenta has multipotent stem cells.

Adult bone marrow can produce different cells to repair those with particular tissue or organs.

Question 7

How to combat issues with pluripotent stem cells?

Answer 7

iPS cells —> produced from adult somatic stem cells by using transcription factors.

Overcomes ethical issues.