Summary Topic 3 Epigenetics

Epigenetics
Epigenetic modification -
covalent
modification
to DNA chromatic


Epigenome -
all epigenetic modification (inheritable)
S.I units
DNA wrapped around
is 8 protein molecules called
histores with tails
↳ Cluster
sticking out
he
of proteins

↳ multiple clusters per
gene

DNA negative
: Histones =
Positive
Togeher makes Chromatin

Heterochromatin-tightly wound DNA (genes switched
off)
Euchromatin DNA (genes switched on
loosely wound are
-




Tightly wound = no transcription due to DNA
unwinding
↳
bind
no
binding
to he
of RNA
promoter
polymerase + transcriptionfactors
.




Stimulus will trigger
Basis : signals which add
modifications
to he tails those proteins I make it
of easier
for
the gene to be switched on

↳
driving gene expression
.




If switch
stimulus is removed new modifications to tails will


off gene
.




Specific Histore
acetylation-adding (CH3(0)
an
acetyl group
DNA :
negatively charged
Acetyl protein is
negatively charged

repels DNA >
- loosen attraction between DNA and histore
proteins
=
Enchromatin