Unit 8 - Gene Control

Question 1

How do alterations to tumour suppressor genes lead to cancer (4)

Answer 1

1. Increased methylation
2. Mutation
3. Tumour suppressor genes are not transcribed/expressed
4. Results in rapid uncontrollable cell division

Question 2

What is a transcription factor? (3)

Answer 2

1. Protein that moves from cytoplasm to DNA
2. TF binds to specific gene
3. Leads to blocks (pre) mRNA production

Question 3

How does oestrogen stimulate transcription? (6)

Answer 3

1. Oestrogen diffuses through the cell membrane
2. Attaches to receptors
3. Receptors change shape
4. Receptor leaves protein complex which inhibited its action
5. Oestrogen receptor binds to promoter region
6. Enables RNA polymerase to transcribe target genes

Question 4

Describe RNA interference?

Answer 4

1. MicroRNA/SiRNA binds to cells mRNA by specific base pairing
2. Prevents mRNA being read by ribosomes
3. Prevents translation