Transcription factors
off when they needed
genes can be switched are not
·
which prevents cellular resources
wasted
being
Typical human cells express 3-5 of their genes
·
% at
time.
any given
cancer can be a result of genes not turning off properly
transcription factors more into the nucleus bind to DNA
·
from the
cytoplasm and .
↳ This DNA and the activated
binding causes a change in the
gene
is
RNA attaches to the DNA chain and transcription wil start the
polymerase then
synthesis of pre-mRNA
a
specific number of transcription factors is needed to activate a
gene
transcription factors are regulated by signals produced from other molecules
Inhibitor molecules prevent transcription factors from binding to the DNA preventing ,
transcription and
polypeptide synthesis because the site of transcription is inactive
Effect of destrogen on
gene transcription
O
destrogen diffuses through phospholipid cell
surface membrane into the cytoplasm
② There are transcription factors inside the cytoplasm
③ binds to
destrogen a site on the receptor molecule ,
as they have complementary shapes
① the shape the inhibitor leave the trans
destrogen changes of the recepter ,
causing to
cription
falter
⑤
Transcription factor can now enter the nucleus via nuclear pores to bind with DNA
⑥ This stimulates the transcription of the
gene which makes up the portion of DNA
, epigenetics
only occurs
in
eukaryotes
heriable
epigenetics involves
changes in
gene function without changing
·
,
the base sequence of DNA
These changes are caused by changes in the environment that inhibit
transcription by :
↳ increased
methylation of DNA
↳ decreased acetylation of associated histones
methylation
added to
·
during DNA
methylation ,
a
methyl group is a carbon atem 5 of a
residue
cytosine
methylated CpG repeats 'silence' genes
repeated CpG sequences are common in the DNA near
gene promders
The presence of repeated Cp6 sequences near promoter inhibits the
·
gene
activity of the enzyme RNA
paymerase.
-
As cannot be transcribed
a result the
affected gene so it is
effectively
-
,
silenced .
Histone fails
histone molecules have side branches or tails
,
These tails contain amino acid leucine
·
↳ Leucine acetylated
can be ,
which makes histones more
loosely packed
, RNA interference (RNAil
some
In eukaryotes and prokaryotes translation of the MRWA produced from target
·
,
genes can be inhibited by RNA interference.
·
This is when MRWA that has already been transcribed gets destroyed
before it is translated to create a
polypeptide chain
↳ This is done by a small interfering RWA-siRNA
In more detail ...
·
An
enzyme can cut the SiRNA
MRWA into
·
One strand of the SiRWA combines With another enzyme
This SiRNA-enzyme complex will bind via complementary base pairing to
another MRWA molecule
·
Once bound ,
the enzyme will cut up mRNA so it cannot be translated
off when they needed
genes can be switched are not
·
which prevents cellular resources
wasted
being
Typical human cells express 3-5 of their genes
·
% at
time.
any given
cancer can be a result of genes not turning off properly
transcription factors more into the nucleus bind to DNA
·
from the
cytoplasm and .
↳ This DNA and the activated
binding causes a change in the
gene
is
RNA attaches to the DNA chain and transcription wil start the
polymerase then
synthesis of pre-mRNA
a
specific number of transcription factors is needed to activate a
gene
transcription factors are regulated by signals produced from other molecules
Inhibitor molecules prevent transcription factors from binding to the DNA preventing ,
transcription and
polypeptide synthesis because the site of transcription is inactive
Effect of destrogen on
gene transcription
O
destrogen diffuses through phospholipid cell
surface membrane into the cytoplasm
② There are transcription factors inside the cytoplasm
③ binds to
destrogen a site on the receptor molecule ,
as they have complementary shapes
① the shape the inhibitor leave the trans
destrogen changes of the recepter ,
causing to
cription
falter
⑤
Transcription factor can now enter the nucleus via nuclear pores to bind with DNA
⑥ This stimulates the transcription of the
gene which makes up the portion of DNA
, epigenetics
only occurs
in
eukaryotes
heriable
epigenetics involves
changes in
gene function without changing
·
,
the base sequence of DNA
These changes are caused by changes in the environment that inhibit
transcription by :
↳ increased
methylation of DNA
↳ decreased acetylation of associated histones
methylation
added to
·
during DNA
methylation ,
a
methyl group is a carbon atem 5 of a
residue
cytosine
methylated CpG repeats 'silence' genes
repeated CpG sequences are common in the DNA near
gene promders
The presence of repeated Cp6 sequences near promoter inhibits the
·
gene
activity of the enzyme RNA
paymerase.
-
As cannot be transcribed
a result the
affected gene so it is
effectively
-
,
silenced .
Histone fails
histone molecules have side branches or tails
,
These tails contain amino acid leucine
·
↳ Leucine acetylated
can be ,
which makes histones more
loosely packed
, RNA interference (RNAil
some
In eukaryotes and prokaryotes translation of the MRWA produced from target
·
,
genes can be inhibited by RNA interference.
·
This is when MRWA that has already been transcribed gets destroyed
before it is translated to create a
polypeptide chain
↳ This is done by a small interfering RWA-siRNA
In more detail ...
·
An
enzyme can cut the SiRNA
MRWA into
·
One strand of the SiRWA combines With another enzyme
This SiRNA-enzyme complex will bind via complementary base pairing to
another MRWA molecule
·
Once bound ,
the enzyme will cut up mRNA so it cannot be translated
