Epigenetics

Question 1

What is Epigenetics?

Answer 1

It controls whether a gene is expressed or not by attaching or removing an epigenetic marker

Question 2

What do epigenetic markers do?

Answer 2

• do not alter the sequence of DNA
• they alter how easy it is for enzymes to access DNA in order to carry out transcription

Question 3

What factors affect epigenetic markers?

Answer 3

• environmental factors such as diet and smoking
• epigenetic changes are also heritable so pass down onto the next generation

Question 4

What happens as a result of methylation of DNA?

Answer 4

• 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

Question 5

What happens as a result of acetylation of histones?

Answer 5

• 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.