epigenetics

Question 1

what is epigenetics

Answer 1

the study of heritable changes NOT caused by changes in the DNA

the altering of gene expression

Question 2

what is gene expression

Answer 2

genes may be ‘on’ or ‘off’ through chemical reactions

Question 3

what causes epigenetic changes

Answer 3

environmental factors such as diet, exercise, education, mental status, family

Question 4

can epigenetic changes be inherited

Answer 4

yes they can be inherited by offspring so what you do in your lifetime may cause changes that affect your offspring

Question 5

chromatin

Answer 5

DNA in a non dividing cell
long thready strands

Question 6

histones

Answer 6

proteins in the DNA strand that the DNA coils around

Question 7

what are the 2 types of histone modification

Answer 7

histone acetylation and histone deacetylation

Question 8

histone acetylation

Answer 8

enhances gene expression

• the addition of an acetyl group to a histone tail
• causes DNA to relax so it is loose and transcription can occur

Question 9

eg of histone acetylation

Answer 9

cancer: tobacco, diet and pollution can lead to histone acetylation of oncogene activation and tumor progression

Question 10

histone deacetylation

Answer 10

inhibits gene expression

• an enzyme ill remove the acetyl group from the histone tail
• causes DNA to coil tightly so transcription can occur

Question 11

DNA methylation

Answer 11

• the addition of a methyl group to a DNA molecule
  (acts as a chemical cap that stops a part of DNA being read)
• stops DNA being red and therefore inhibits gene expression

Question 12

why is DNA methylation bad in some cases

Answer 12

problems arise when it occurs to specific genes such as the tumor supressor gene