Stem cells 1 - why stem cells?

Question 1

What are 3 cells that are renewing continuously?

Answer 1

• blood
• skin
• germ cells

Question 2

What are 3 cells that undergo regeneration after injury?

Answer 2

• muscle
• pancreas
• liver

Question 3

Why do we need stem cells?

Answer 3

• some differentiated cells are so differentiated they do not have a nucleus - cannot renew themselves
• some cells in the immune system loose DNA during differentiation
• tissues need new cells

Question 4

briefly explain the differentiation of a stem cell

Answer 4

• is immortal
• divides slowly
• generates fast dividing daughters with limited lifespan
• final differentiate cell may be non-proliferative with limited life span

Question 5

What are the two different ways a stem cell can divide?

Answer 5

• symmetrical - produced 2 stem cells or 2 differentiated cells
• asymmetrical - produces one stem cell and one differentiated cell

Question 6

What are the factors that can generate asymmetrical division?

Answer 6

• environmental
• localised cell components

Question 7

How were stem cells discovered?

Answer 7

• when mice were treated with radiation then had bone marrow transplantations, colonies of cells formed from one cell
• colonies contained differentiated cells

Question 8

explain plant stem cells

Answer 8

• multicellularity evolved separately in plants and animals
• suggests that stem cells are a good solution