epigenetic control of gene expression

Question 1

what is epigenetics

Answer 1

heritable change in gene function without changing dna base sequence

these changes are caused by enviroment
can inhibit transcription

Question 2

what is the epigenome

Answer 2

a single layer of chemical tags on teh dna

Question 3

what does the epigenome do?

Answer 3

impacts the shape of the dna histone
- whether it is tightly wound so gene wont be expressed or unwound so it will be expressed

Question 4

what are the two key chemical tags?

Answer 4

• methyl
• acetyl

Question 5

what happens when methyl groups are added to DNA

Answer 5

inhibits transcription

Question 6

why does methylation of dna inhibit transcription?

Answer 6

• methyl groups cause chromatin to become condense/tightly bound
• so trancription actors can no longer bind
• this prevents transcription from occuring

Question 7

what happens when acetyl groups are removed from DNA

Answer 7

inhibits transcription

Question 7

how does decreased acetylation of dna affect gene transcription

Answer 7

• decreasing acetylation increases positive charge of histones
• positively charged histones bind to negatively charged dna
• binding becomes too tight (histones and dna strongly associated) and prevents transcriptions factors binding
• this prevents trasncription

Question 8

what are transcription factors?

Answer 8

a protein that controls the transcription of genes by binding to a specific region of dna