8 p2

Question 1

what can ips do

Answer 1

• changing of unipotent cells to pluropotent cells using transcription factors

Question 2

Describe the structure of transcription factors

Answer 2

-each part of a transcription factor is complementary to a shape to a particular sequqnce of nucleotides in a promoter sequence

Question 3

How is oestrogen expressed ?

Answer 3

• oestrogen is a lipid soluble so can diffuse through the membrane
• oestrogen binds to the receptor protein that’s part of a transcription factor
  -transcription factor moves to the nucleus
• oestrogen has changed the shape of the transcriptional factor so it can complementarty bind to the promoter region of a specific gene
• this allows RNA polymerase to attatch to a gene and cataylse transcription
• mRNA is transcribed from gene
• mRNA is translated into protein.

Question 4

What can oestrogen cause and why

Answer 4

-cancer
high blood concentrations of oestrogen over a period of time can increase the risk of uncontrollable cell division.

Question 5

Whats the drug used to treat cancer and what does it do

Answer 5

-tamoxifen
-tamoxifen is converted to endoxifen which has a similar structure to oestrogen
-edoxifen competes with oestrogenfor binding to the oestrogen receptor , inhibiting the effect of oestrogen.

Question 6

describer the structure of siRNA

Answer 6

-small double stranded molecules of RNA

Question 7

What does siRNA do

Answer 7

regulates gene expression by causing mRNA to be broken down after transcription so prevents translation

Question 8

how does siRNA prevent translation?

Answer 8

-RNA molecule is hydrolysed into smaller segments by an enzyme
-Becomes single stranded siRNA
-siRNA binds to a specific enzyme that hydrolyses mRNA
-siRNA binds to a specific molecule of mRNA by complementary base paring
-the enzyme hydrolyses the mRNA molecule preventing translation of mRNA into protein.