Epigenetics

How is it possible to have cells with the same DNA and diffrent functions

even though all of our cells have the same genes they dont express the same ones

Gene expression

refers to each cells unique combination of genes that are translated into proteins

Proteins job in cells

gives cells their functions

epigenetics

refers to any factor that influences gene expression

Asymmetric cell division

term for when cells produced in mitosis inherit diffrent “factors” despite inheriting the same DNA

what do the factors do

influence cell division

2 types of epigenetic factors

1. Transcription factors

2. Histone modifiers

Transcription factors

Proteins that either recruit or block RNA polymerase from binding to a gene

• Bind directly to special DNA sequences around the gnes

recruiting RNA polymerase

leads to gene expression

blocking RNA polymerase

leads to no gene expression

Histones

A protein that DNA is wrapped around to help compact it

Histone structure

Histone complexes are composed of 8 individual histone proteins. Have tails that are chains of amino acids

Histone modification

Histones can either compact or loosen DNA by addign diffrent groups

what does the methyl group do on histones

causes histone to pack together

what does the Acetyl group do on histones

keeps DNA open

Histone methylates

adds methyl groups

Histone acetylates

adds acetylene groups

Compacted DNA

heterochromatic

Open DNA

euchromatin

RNA polymerase can’t preform transcription on what type of DNA

compacted