1
Q
What is Epigenetics?
A
It controls whether a gene is expressed or not by attaching or removing an epigenetic marker
2
Q
What do epigenetic markers do?
A
- do not alter the sequence of DNA
- they alter how easy it is for enzymes to access DNA in order to carry out transcription
3
Q
What factors affect epigenetic markers?
A
- environmental factors such as diet and smoking
- epigenetic changes are also heritable so pass down onto the next generation
4
Q
What happens as a result of methylation of DNA?
A
- A methyl group attaches to CpG site, joined by a phosphodiester bond
- The methyl group is added to cytosine by enzymes called methyltransferases
- increased methylation makes DNA more condensed so that DNA Helicase/RNA polymerase cannot interact with the DNA so transcription cannot occur
5
Q
What happens as a result of acetylation of histones?
A
- DNA is wrapped around histone proteins to produce chromatin which can be highly condensed or less condensed
- increased acetylation causes chromatin to be less condensed, this allows transcription to occur more easily because enzymes involved in transcription can easily access the DNA.
