Cell Division

Question 1

Potency definition

Types of potency with examples

Answer 1

A stem cell’s ability to differentiate into different types of cells.

Totipotent- can differentiate into any type of cell (and form entire organisms). Example: a fertilised egg/zygote.

Pluripotent- Can differentiate into any type of cell, but can’t form entire organisms. Example: the stem cells present in embryos that differentiate later into tissues (blastocyte)

Multipotent- can only differentiate into a range of cells within a type of tissue. Example: stem cells in bone marrow.

Question 2

Where are stem cells found in:
Plants
Animals

Answer 2

Plants: Meristem, vascular cambium
Humans: Embryonic stem cells, human ctem cells

Embryonic- totipotent in first 7 days, then blastocytes forms, now pluripotent.
Adult stem cell- stem cells in bone marrow, umbilical chord.

Question 3

Use of stem cells in medical research

Ethical issues with removing stem cells from embryos

Answer 3

-Stem cell tissue used to study how certain cells develop
-Stem cells used to test the side effects of a new drug
-Stem cells used to test the effectiveness of new medicinal drugs.

-Results in the destruction of the embryos- seen as murder
-Embryo has not given consent

Question 4

Use of stem cells in specific diseases

Answer 4

Alzheimers- death of nerve cells in the brain causes memory loss. Stem cells grown into healthy nerve cells.

Parkinsons- Loss of dopamine producing nerve cells in brain causes tremours. Stem cells grown into dopamine producing cells.

Type 1 diabetes- damage to B cells.

Macular regeneration- causes blindness in elderly

Heart disease- damaged heart
Spinal injuries
Birth defects

Question 5

What is a tissue
What is an organ

Answer 5

A collection of cells that are adapted to work together and carry out a specific function in the tissue.

A collection of tissues that are adapted to work together and carry out a specific function in the organ.