7.2.4 - Uses of stem cells

Question 1

Describe the stem cell theory.

Answer 1

The use of embryonic stem cells has not had the success hoped as its difficult to control differentiation.
Using a person’s own adult stem cells to repair tissue removes the issue of rejection and is a more ethical way of using them.

Question 2

What is used to trial induced pluripotent stem cells in humans?

Answer 2

A modified virus carrying human genes

Question 3

How are researchers trying to make induced pluripotent stem cells, what is the method?

Answer 3

The virus enters human cells and inserts the genes into the host DNA.
Researchers have introduced certain transcription factors back into the cell which allows them to be pluripotent.

Question 4

What are the benefits of using induced pluripotent stem cells instead of embryonic stem cells?

Answer 4

There is a reduced risk of infection
Removes ethical issues that come with embryonic stem cells

Question 5

What is therapeutic cloning?

Answer 5

An experimental technique to produce large quantities of healthy tissue.
e.g making cells to replace damaged pancreas

Question 6

What are the steps in therapeutic cloning?

Answer 6

1) Nucleus removed from a pateint’s body cell
2) Transferred to a human ovum which has its nucleus removed, fused together with an electric shock which causes further development.
3) Pre embryo starts to develop and divide, producing embryonic stem cells
4) The genetics perfectly match the patient. The stem cells can be collected and cultured in a suitable environment to differentiate into the tissue needed
5) They can be transferred back into the patient

Question 7

Why are there less ethical issues with the use of adult stem cells than embryonic stem cells?

Answer 7

When embryonic stem cells are taken from an embryo, the embryo is destroyed.