using stem cells- lqc 4b

Question 1

uses of stem cells in medical therapies

Answer 1

• To inject into the body to give rise to specialised cells to replace dead or damaged cells, to repair damaged tissue
• Producing tissues or organs for transplant
• To treat a wide range of diseases that are caused by faulty or damaged cells e.g. heart disease, Type 1 diabetes, spinal cord injuries

Question 2

therapeutic cloning

Answer 2

The nucleus is removed from an egg cell. A diploid somatic cell is
removed from the patient and the nucleus from this cell is placed in the egg cell. The new cell is
stimulated using electricity to divide by mitosis to form a blastocyst .
Pluripotent stem cells are removed and encouraged to develop into tissues/organs which are
genetically identical to those of the patient, which can be used for transplantation.
The advantages of therapeutic cloning are that the transplanted tissue is not rejected
by the patient, as the cells are genetically identical to the patient’s own cells, so there is no need
for the patient to take immunosuppressant drugs.

Question 3

induced pluripotent cells

Answer 3

Induced pluripotent stem cells are adult/multipotent somatic cells which have been genetically reprogrammed to become like embryonic stem cells, by being forced to express genes and factors important for maintaining the defining properties of embryonic stem cells.

Question 4

roles of the human fertilisation and embryology authority

Answer 4

1. To decide on the maximum age of an embryo allowed to be used for research
2. To consider ethical issues, especially for the use of human embryos
3. To check that the source of the stem cells is acceptable
4. To stop human cloning
5. To stop the unnecessary repeating of research
6. To ensure research institutions have a licence to carry out research

Question 5

disadvantages of adult stem cells

Answer 5

Are multipotent (rather than totipotent or pluripotent)
Can only give rise to a small/ limited range of different tissues
Very few of these stem cells are present within the human body
Difficult to extract from some parts of the body eg. brain

Question 6

disadvantages of embryonic stem cells

Answer 6

Ethical issues (as cells are obtained from spare embryos in IVF)
Risk of rejection , infection or cancer when used in treatments

Question 7

disadvantages of induced pluripotent stem cells

Answer 7

Difficult to create pluripotent cells
Difficult to control differentiation – may lead to cancer

Question 8

ethical arguments for the use of embryonic stem cells

Answer 8

• Offers treatment to many people who are

suffering from a disease eg. Parkinson’s, Alzheimer’s

• Research using multipotent stem cells is progressing more slowly
• If we ban it in the UK, it will still happen in
  other countries
• Spare IVF embryos would be
  destroyed anyway
• Research with embryonic stem cells is
  needed to develop use of adult/multipotent stem cells
• An embryo is not considered to be a new
  human until it is viable

Question 9

ethical arguments against the use of embryonic stem cells

Answer 9

• Embryonic stem cells are from embryos which are considered to be unborn
  children , so using them is
  effectively murder
• Much embryonic stem cell treatment may be
  fraudulent / badly regulated / exploits suffering / encourages IVF clinics to ‘create’ more ‘spare’ embryos
• If we wait a few years longer we may have
  the same benefits through multipotent
  stem cells
• Diverts funding away from alternatives e.g. adult stem cells
• An embryo becomes a new human at the
  moment of conception