Epigenetics

Question 1

Histones

Answer 1

DNA wrapped around histones and how closely the DNA and histones are packed together affects transcription

Question 2

Epigenetics

Answer 2

Heritable changes in gene function without changes to the base sequence of DNA, caused by changes in the environment

Question 3

Epigenetics can inhibit transcription . How?

Answer 3

Increased methylation of DNA
Decreased Acetylation of histones

Question 4

Methylation of DNA

Answer 4

Methyl groups added to cytosine bases in DNA
Nucleosome pack more tightly together which prevents trnscription factors from binding so genes are not transcribed

Irreversible

Question 5

Acetylation of histones

Answer 5

Decreased acetylation increases positive charge of histones
Histones bind DNA (which are negatively charged) more tightly so prevents transcription factors binding so genes are not transcribed.

Reversible

Question 6

Relevance of epigenetics on disease

Answer 6

Can increase expression on oncogene or silence a tumour suppressor gene which can lead to tumour development

Too see if someone has abnormal levels of methyl or acetyl - early indicator of cancer (called biomarker)

Could be manipulated to treat cancer e.g. drugs that prevent histone acetylation/ or DNA methylation