CELLUR DIFFERENTIATION U1

Question 1

Explain the meaning of cellular differentiation

Answer 1

Cellular differentiation is the process by which a cell expresses certain genes to produce proteins characteristic for that type of cell. This allows the cell to carry out specialised functions.

Question 2

State the function of a meristem

Answer 2

Meristems are where cellular differentiation takes place in plants.

Meristems are regions of unspecialised cells that can divide and self-renew.

There are 2 types of meristems:

Apical meristems – found on the tips of shoots and roots.
Lateral meristems – found within the stem.

Question 3

State the 2 types of stem cells and the function of stem cells in animals

Answer 3

The two types of stem cells are:

Embryonic stem cells.
Tissue (adult) stem cells.
Stem cells are unspecialised cells in animals that can divide (or self-renew) and/or differentiate.

Question 4

Describe an embryonic stem cell using the term ‘pluripotent’

Answer 4

Cells in an early embryo can differentiate into all cell types that make up the organism.

All the genes in an embryonic stem cell can be switched on so these types of cells can differentiate into any cell types. Embryonic stems are therefore pluripotent as they can differentiate into ANY cell type.

Question 5

Describe a tissue stem cell

Answer 5

Tissue stem cells are involved in the growth, repair and renewal of cells found in a particular tissue.

Question 6

Explain the term ‘multipotent’ in relation to tissue stem cells

Answer 6

Tissue stem cells are multipotent as they can differentiate into all the types of cell found in a particular tissue type.

For example: Blood stem cells located in the bone marrow can only give rise to all types of blood cells. As they can only differentiate into cells of that particular tissue type, they are multipotent.

Question 7

Describe how stem cells are used therapeutically and in research

Answer 7

The therapeutic uses of stem cells involve the repair of damaged or diseased organs or tissues. Under the right conditions, in the laboratory, embryonic stem cells can self-renew.

Examples are the use in corneal repair and the regeneration of damaged skin.

Stem cell research provides information on cell processes such as cell growth, differentiation and gene regulation. Stem cells are used as model cells to study how diseases develop or being used in drug testing.

Question 8

Describe ethical issues associated with using embryonic stem cells

Answer 8

Use of embryonic stem cells can offer effective treatments for disease and injury; however, it involves the destruction of embryos.