8.2.1 Most Of A Cells DNA isnt Translocated

Question 1

What are stem cells

Answer 1

Undifferentiated cells

Capable of :
-dividing (mitosis) to replaces themselfs
- differentiating into specialised cells

Question 2

How do stem cells specialise

Answer 2

Stimuli lead to activation of same genes (transcription factors)

So mRNA is transcribed from these genes and then translated to form proteins

They proteins modify cells permanently and determine their function

Question 3

Totipotent cells

Answer 3

Occurs for a limited time in early mammalian embryos

Can divide and differentiate into any type of body cell

Question 4

Pluripotent cells

Answer 4

Found in mammalian embryos

Can divide and differentiate into most cells (not placental cells)

Question 5

Multipotent cells

Answer 5

Found in mature mammals

Can divide and differentiate into a limited number of cells (bone marrow)

Question 6

Unipotent cells

Answer 6

Mature mammals

Can divide and differentiate into 1 cell type

E.g. unipotent cells in heart can differentiate into cardiomyocytes (cardiac muscles cells)

Question 7

How can stem cells used in treatment

Answer 7

Transplanted into patients to divide into unlimited numbers

Then differentiate into required healthy cells to replace damaged cells

Question 8

Exsample

Answer 8

Type 1 diabetes

Bone marrow stem cells transplant for sickle cell diseases:
-destroy patients bone marrows before treatment so no faulty cells
-transplant stem cells from healthy, divide and differentiate into healthy cells

Question 9

How are induced pluripotent cells produced

Answer 9

Obtain adult somatic(body) cells from patient

Add specific protein transcription factors:
-they attach to promoter regions of DNA, stimulating or inhibition transcription

Culture cells allow them to divide by mitosis

Question 10

Use of stem cells in treating human disorders

Answer 10

Pros:
-could realise human suffering, saving lives and improving quality of life
-embryos are often left over from IVF, would otherwise be destroyed
-IPS unlikely to be rejected
-IPS can be made without embryo

Against:
-ethical issues with embryonic stem cells transplant
-immune system can reject cells and immunosuppressants drugs are req.
-cells could divide out of control (cancer)