Human Biology (Stem Cells)

Question 1

Describe Differentiation and an example

Answer 1

. The process by which cells become specialised is called differentiation.

As the cells undergo division by mitosis, different genes become activated. This makes the cells differentiate into specialised cells that can perform particular functions – for example, stomach cells that secrete enzymes.

Question 2

What type of cells undergo differentiation?

Answer 2

The cells that can undergo differentiation are called stem cells.

Question 3

What makes stem cells different to normal cells?

Answer 3

They are very different from other cells because they are not specialised for any particular role and are capable of repeated division by mitosis.

Question 4

What are stem cells classified based on?

Answer 4

Stem cells can be classified based on where they originate (embryonic, adult or cord blood) or the type of cells that they can form.

Question 5

What are stem cells?

Answer 5

Generalised cells that are capable of differentiating into a range of possible cell types.

Question 6

What are totipotent stem cells?

Answer 6

Totipotent stem cells have the potential to differentiate into ANY cell e.g. all body cells AND embryonic layer (e.g. amnion, chorion)

Question 7

Where are totipotent stem cells found?

Answer 7

The zygote and the trophoblast (outer layer of the embryo) consists of totipotent stem cells.

Question 8

What are pluripotent stem cells?

Answer 8

Pluripotent stem cells can become any cell of the body but not the embryonic layers.

Question 9

Where are pluripotent stem cells found?

Answer 9

The embryoblast (inner cell mass) consists of pluripotent stem cells.

Question 10

What are multipotent stem cells?

Answer 10

Multipotent stem cells are able to differentiate into a small group of specialised cells e.g. a blood stem cell