Stem Cells

Question 1

Define stem cell

Answer 1

A unspecialised cell that can divide and differentiate to become different types of cell for the whole of the organism’s life time

Question 2

Define “totipotent”

Answer 2

The ability of a cell to differentiate into all specialised cell types
Including extra embryonic cells (e.g placenta)

Question 3

Where can totipotent stem cells be found?

Answer 3

Very early mammalian embryos

Question 4

Define “pluripotent”

Answer 4

The ability of a cell to differentiate into all specialised cell types within an organism but not extra embryonic cells

Question 5

Define “multipotent”

Answer 5

The ability of a cell to differentiate into a few types of specialised cell

Question 6

Where can multipotent stem cells be found?

Answer 6

Bone marrow

Question 7

Define “differentiation”

Answer 7

The process by which a cell becomes specialised

Question 8

How do cells become specialised in animals?

Answer 8

• All cells contain all of an organism’s DNA
• Conditions within cells control which genes are expressed (transcribed and translated) into proteins
• Changes internal environment of cell
• Affects transcription of other genes
• Cells become specialised - this is irreversible

Question 9

What can embryonic stem cells be used for?

Answer 9

• Repair

- Transplantation

Question 10

What type of injuries could embryonic stem cells be used to treat?

Answer 10

• Spinal cord injuries

- Heart disease and damage caused by heart attacks

Question 11

What are the two ways immune system problems with stem cells can be overcome?

Answer 11

• Immunosuppressant drugs

- Tissue typing

Question 12

How can embryonic stem cells be obtained? 4

Answer 12

• Embryos created in lab using IVF
• Egg cells fertilised by sperm outside the womb
• Once embryos = 4 - 5 days, stem cells removed from them
• Rest of embryo destroyed

Question 13

What can adult stem cells treat?

Answer 13

• Leukaemia (WBCs and RBCs)

- Burns (skin cells)

Question 14

How are adult stem cells obtained?

Answer 14

• Relatively simple operation with little risk but discomfort
• Donor anaesthetised, needle inserted into bone centre
• Small quantity of bone marrow is removed

Question 15

What is the difference between plant and animal cells in terms of stem cells?

Answer 15

Plant cells remain totipotent all their life - differentiated cells can redifferentiate and develop into new plants entirely

Question 16

How is plant cells always being totipotent useful?

Answer 16

Gardeners regenerate whole plant clones from root, stem and leaf cuttings

Question 17

What is the main objection to using stem cells?

Answer 17

Many believe embryo destruction is wrong as they believe genetically unique individual formed has a right to life

Question 18

What 5 things do regulatory bodies do?

Answer 18

• Decide if proposals of research should be allowed
• Licensing and monitoring centres of research e.g stem cell research: avoids unregulated research and ensures researchers are fully trained
• Produces guidelines and codes of practice, ensures all scientists work in a similar manner
• Monitoring developments in scientific research, ensuring guidlines are up to date
• Providing information and advice to government and professionals

Question 19

What are the advantages of stem cells?

Answer 19

• Saves lives
• Improves quality of life
• Prevents suffering

Question 20

How could the objection to embryonic stem cells be worked around? And what is the problem with this solution?

Answer 20

• Use unfertilised eggs triggered to divide

- But adult stem cells not pluripotent

Question 21

What are the risks of using stem cell treatment?

Answer 21

• Infection from the donor
• Risk of infection from contaminated equipment during the procedure
• Risk of cancer
• Rejection from immune system
• Increased susceptibility to infections due to immunosuppressant drugs