Cell specialization 1.1

Question 1

2 key qualities of stem cells

Answer 1

1. Self-Renewal – They can continuously divide and replicate
2. Potency – They have the capacity to differentiate

Question 2

Stem cells

Answer 2

Unspecialized cells

Question 3

There are four main types of stem cells during human development

Answer 3

• Totipotent – Can form any cell type, as well as extra-embryonic tissue
• Pluripotent – Can form any cell type (e.g. embryonic stem cells)
• Multipotent – Can differentiate into closely related cell types
• Unipotent – Cannot differentiate, but are capable of self-renewal

Question 4

Stem Cell Therapy

Answer 4

Stem cells can replace damaged or diseased cells with healthy ones

Question 5

The therapeutic use of stem cells involves:

Answer 5

• Harvesting stem cells from appropriate sources
• Using biochemical solutions to trigger cell differentiation
• Surgically implanting new cells into patient’s own tissue
• Suppressing the host immune system to prevent rejection
• Monitoring new cells to ensure they do not become cancerous

Question 6

Therapeutic Examples

Answer 6

Stargardt’s disease, Macular degeneration, Replace defective retinal cells

Question 7

Ethics of Stem Cell Use

Answer 7

Sourced from embryo’s, umbilical’s Cord blood and adult tissue

Question 8

Cell Differentiation

Answer 8

All cells of an organism contain an identical genome – each cell
contains the entire set of genetic instructions for that organism

Differentiation involves the expression of some genes and not
others in the cell’s genome (selective gene expression)

The activation of different genes within a given cell will cause it
to develop differently from other cells (i.e. cell specialization)

Question 9

Gene Packaging

Answer 9

Within the nuclei of eukaryotic cells, gene instructions
(DNA) are packaged with proteins as chromatin