Cancer- ppqs Flashcards
Describe how alterations to tumour suppressor genes can lead to development of tumours
- (Increased) methylation (of tumour suppressor genes)
- Mutation (in tumour suppressor genes)
- Tumour suppressor genes are not transcribed/ expressed
OR
Amino acid sequence/ primary structure altered - (Results in) rapid/ uncontrollable cell division
Enzyme called ATM binds to broken DNA, leading to activation of a protein coded for by a tumour suppressor gene. Effect of ATM is to stop cell division until DNA is repaired.
A mutation could result in a person having non-functional forms of gene that produces ATM.
What are possible effects of this non-functional form of ATM?
- ATM will not bind to (broken) DNA
- DNA not repaired/ cell still has broken DNA
- Cell division continues/ tumour forms
- Tumour suppressor (gene) not effective/ not activated
- May have no effect in diploid/ heterozygous (organism)
- (Which) still has a functional ATM/ ATM gene
Define what is meant by epigenetics
- Heritable changes in gene function
- Without changes to base sequence of DNA
What does oestrogen bind to when acting as a control factor of transcription?
- Binds with protein
What do methyl groups bind to when acting as a control factor in transcription?
Binds with DNA
What do acetyl groups bind to when acting as a control factor in transcription?
Binds with protein
Explain how increased methylation could lead to cancer
- Methyl groups (could be) added to (both copies of) a tumour suppressor gene
- The transcription of tumour suppressor genes in inhibited
- Leading to uncontrolled cell division
Explain how the methylation of a tumour suppressor gene could lead to cancer
- Methylation prevents transcription of gene
- Protein not produced that prevents cell division/ causes cell death/ apoptosis
- No control of mitosis
