Epigenetics

Define chromatin

DNA associated with histones

Define epigenome

Chromatin coverd in chemical tags

Define heterochromatin

When DNA and his tones are tightly wound and no gene expression occurs

Define euchromatin

Loosely packed histones and DNA, gene expression can occur at promoter regions

Define what is meant by epigenetics

When environmental factors can cause heritable changes in gene expression without changes to the DNA base sequence

How does epigenetic silencing occur? (2 marks)

When the Epigenome keeps genes inactive, by keeping them tightly packed and cannot be read.

Suggest 2 ways can cancer be caused by

Epigenetic factors, stopping the expression of a gene

A mutation in the tumour suppressor genes- the cell cycle cannot be controlled