8 - CONTROL OF GENE EXPRESSION

Question 1

Describe how stem cells become specialised

Answer 1

• Stem cells become specialised by only expressing certain genes and switching off others.
• Genes that are expressed get transcribed into mRNA, which is then translated into proteins.
• These proteins modify the cell.
• Changes to the cell produced by the proteins cause the cell to become specialised.

Question 2

What are stem cells?

Answer 2

Unspecialised cells that can develop into other types of cell

Question 3

State the different types of stem cells

Answer 3

Totipotent - can develop into any type of body cell
Pluripotent - can develop into any type of body cell but cannot become the cells that make the placenta
Multipotent - can differentiate into a few different types of cell
Unipotent - can only differentiate into one type of cell

Question 4

What are cardiomyocytes

Answer 4

Heart muscle cells

Question 5

Describe the regulation of transcription

Answer 5

1. Transcription factors move from cytoplasm to nucleus
2. Bind to DNA at a specific DNA base sequence on a promoter region (before / upstream of target gene)
3. This stimulates or inhibits transcription (production of mRNA) of target gene(s) by helping or
   preventing RNA polymerase binding

Question 6

What are induced pluripotent cells?

Answer 6

Adult somatic cells that have properties of pluripotent stem cells
-> due to being treated with transcription factors that switch on genes associated with differentiation