Gene expression 2: epigenetics

Question 1

Overview

Answer 1

Changing transcription by adding or removing chemical groups without modifying a sequence of DNA
Chromatin structure is changed instead
Occur in response to changes in environmental factors

Question 2

Epigenome

Answer 2

A sets of chemical modifications (or tags) associated with DNA or specific amino acid in histone proteins

Question 3

Methylation of DNA

Answer 3

Methyl group attaches to a gene
Binds at a CpG site
Prevents TF binding
Represses gene expression

Question 4

CpG site

Answer 4

Cytosine and guanine next to each other

Question 5

Acetylation of Histones

Answer 5

Acetyl molecules (COCH3) bind to histones and reduce condensation
Allows TF binding and gene expression
Removing acetyl group condenses chromatin and restricts gene expression

Question 6

Condensation of histones

Answer 6

Histones have chromatin DNA wrapped around them
Chromatin can be highly or less condensed
Effects the ability of TFs and DNA polymerase to bind

Question 7

Inheritance of epigenetic changes

Answer 7

Methyl groups passed into daughter cells in replication
If this occurs in gametes the changes can be passes to offspring

Question 8

Non coding RNA (ncRNA)

Answer 8

Made by transcribing DNA that doesn’t code for proteins
Some ncRNA has epigenetic effects
Genes or whole chromosomes can be silenced by ncRNA (x chromosome inactivation)