Summary The entire specification for AQA A-level biology topic 8 gene expression and technology
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Course
Unit 8 - The control of gene expression
Institution
AQA
I meticulously created these AQA A-level Biology notes during my studies, and they helped me achieve an A*. Organised according to the 8-unit specification, each unit has its own dedicated A4 page with all relevant information, making your study sessions streamlined and efficient. Within each unit,...
bene expression
SECTION S
⑬
technology
ALTERATIONS OF BASE SEQUENCES GENE TECHNOLOGY
gene mutations occur
spontanteosly me
in phase interphase
:
of recombinant DNA =
transfer of DNA fragments mom I organism to anomer to
ever changed
it s i l i s create a
Wansgenic organism
an
,
x
a
transgenic organism :
gentically modified organism
OBTAINING DNA FRAGMENTS
maySte stormsaen
-
restriction endonucleases
benzene
verzeanscriptomaker manscritage a
a
UVIX-rays AMPLIFICATION OF DNA
HPV virus
① -
in viro = PCR automated + artifical replication
② in
vivo-gene cloning (generically modified)
,
s a
&enawingnat bondsbetweenCB'separate I cut open the plasmid using restriction enzymes
GENE EXPRESSION : CONTROLLED BY -
③ cooling : allows primers to bind to DNA polymerase >
-
DNA rep IDS !! /
.
2
.
3
use the same
ends of
restriction enzyme to cut out human
gee
Sticky gene + plasmid are complimentary .
① nis
each
ExtendingButpaioinsnuclorides
: - copm. copy
bind by CBD - bonds
F TRASCRIBED
DuAligarcinsnuotidin condensation
4.
MOST A CELIS' DNA IS
OF
racris
·
-
reverse manscriptase
undifferentiated unspecaused specalise 5
Customidinidcocac
5) tem cell a cell that is and has the ability to .
are neatsoa
: ,
PROS certantity of gene in a ·
many copies of MRNA
all with nucleus introns removed
·
specificDNA magments
by splicing -identify OM gene
by looking for mor ner genes
andany bac
totipotent a
=
divide can be extraced 7 insulin
gene only expressed in plasmid it terminate
-
on
trag ments-sticky ends and promotor regions are added So RNA pay starts
·
bryos
~
only
di vi de and >
PLURIP OTE NT :
any
c ype of blood c l 1x plan cet a I cell need to which
-
CONS
mamillian embryos
·
z copies · know cell
that can be used to treat human disorders -
must know sequence around is expressing me gene s t o2 ~
a
interest t wo i n
MULTIPOTENT : divide
imammilian
+ >
-
limited amount of few cen
types geneof no sticky ends -
use mixture
Onto an
of cells + DNA and use inoculating loop to distribute
agar plate with ampicillion agar > colonies m a t
-
adult, mature · extraction - remove inton
have plasmido
haemopoteric repeatIndagainparaunonrecombinant DNA
-
stem a u s con a
UNIPOTENT .
sequences
,
: divide +>
-
cardiomyocytes , in matwe/adult c l s -
INDUCED PLURIPOTENT STEM CELLS : be >
can from adult somatic c u s using appropriate
-
wanscription factors
protein
ipst GENETIC FINGERPRINTING
ADVATAGES DISADVATAGES haemopotolalic UNTR's = variable number tandem repeats , short requence of bases that are repeated
STR = Short tandem repeats
MULTIPOTENT
.emisa of rejection
Letracted) differentiates into DNA with UNTR varies
polymorphic = no repeats
vary :· Length of
·Limited
baasa uNTR is generic fingerprint not
probability organisms havingmesame
:
mfort ·
ips breeding
unlimiteddivisions
risn o ca
r ↳ used wimin forensic science medical , diagnosis , animall plant
E ELECTROPHORESIS
↳
wi
1. DNA samples = DNA extracted from hair / blood/semen
PCR used to amplify DNA Containing UNTR's
.
2 restriction enzymes = endonucleases used to cut into DNA containing UNTR
. Gel
3 electrophoresis-separates Dra fragments by size /length/ charge using
↓me actual size of DNA an electric current so negative DNA
fragments
fragments worked out
by
ningnagment migrated serum And a b
4 . Southern
Blotting :
get
So
is immersed into alkaline solution t
labelled probes can attach later
fragments
blokred from gel onto mylon membrane
no wishot rejen
STEM :
Long lasting ~ GENE
a . DNA
5 Probes = membrane is incubated with DNA proble (radioactive/floresent
:
·
cures as diseased cells probes =7 SS bind to comp UNTR requences .
by CBP
XGENE .
6 filming : wash excess of DNA proble
Virus
muile
ide xray nylon exposed
membrane to
risuorejection
:
XSTEM ,
: mar row
effects Xray hilm
virus inserts in place cancer
.geneticlingerprinting Krayrilms
·
-
X a
aredevelopedNagments
- : that an
a
·
Lack of donors treatments (FR)
repeat
·
not a l l cells modified (disease foresences are used
REGULATION OF TRANSCRIPTION & TRANSLATION GENE SCREENING
they are specific proteins that bind
to target uses of labelled DNA probes + DNA hybridisation
-
TRANSCRIPTION FACTORS genes' promotor region Locates specific aleles of genes
·
transcription
Rua polymerase
·
TF are activators that stimulate RNA polymerase binding to promotor ·
screen patients for heritable conditions/dug respones/health rishs
increases transcription used in generic counselling personalizes medicine
region that +
tactorseor
·
af AT............. TGG
i f are repressors that inhibit RNA polymer a re binding to promotor
sample isampireBypR digested
parientsDu
-
into
·
!
pagments in
is
gene region as blocked by TF , decreases transcription
↳Mparmesanmendingshanded transfered
region a
nylon me
INTERFERENCE
Gestrogen =
hy drophobic)
Steroid based hormone
RNA
wanslated
S .
deation
me membrane is
exposed to
r ays ov to allow of Labelled probes
some genes are manscribed X
PLB in CSM
S imply diffuses through
~
S
in cytoplasm
specific receptors
*
destrogen binds to
gene screening
·
that forms a transcription factor compless
a
this Wanscription factor complex moves > nucleus
disarraubymutana
manyhuman
-
through nuclear pores
mutagenic agents exposure to
as t RN polymerase binding activator to
aquired generic disorders
·
complex = 2)
promotor region of specific genes initialing
manscription
Rishyoryy
· generic counselling
only dus with destrogen receptors are affected by
destrogen used information from gene screening to advice people
who have mutant gene
ances on their . PREVENTION TREATMENT FAMILY PLANNING
options , ,
recessive generic disorde
a
EPIGENETICS invesheritable
by
changes gene
ni
caused 1 in environments
in is
identirecarriers
↑
Cranscription / gene expression :
APPIIACTIONS
: I memulationa nes
·
generically modified crops = silencing riping gas
mitosis
·
METHYLATION : adds Cuz to promotor regions of genes , when cytosine is next to guanine , catalysed by
I t a stuc tue of promotor region . . RNAX bind : prevents manscription
mery transferrerose . d
↑ CETYLATION : adds COCKs to histone proteins catayeed by accly/wansferrerase DNA becomes less .
drop DNA for CO Therefore the RNA polymerase on a s
-
condensed unwavesashistones .
WHY IS EDIGENETIC CONTROL IMPORTANT ?
during normaldevelopment
torepigenemakersauwscusprentiat speciea
·
epigenetic changes t
generic disorders + ↓rish of cancers
·
epigenetic changes can be inherited
·
epigenetic changes are reversable
Drugsindevelopmentomainted
diraxused by
·
we wanted epigenetic changes
inis
GENE EXPRESSION + CANCER
mutated divide rapidly +
uncontrollably
supressor genes and proto oncogenes become
>
tumor
-
When
>
-
malignant cell that form tumors that vary in shape +
grow uniformly
micosis spindleisa
cancersprevenger
repairvening
~ :
i
targets cancer antigens side effects ↑ specific + dose) monoclonal antibodies
, , ,
: immune response to cancer antigens (cytchine therapy (
tumour : mass of abnormal undifferentiated cus produced by uncontrolled mitotic cell division
proto
oncogenesstimates ou a
divideaowschepinscobepas divisions by activating
cel sur face
receptors or coding for growth factors
tumor supressor genes : control cell division stop
c l l division when damage detected) Apoptosis
malignant
cause cancers
cus
X
begnin cus
cause cancers
Mutanonsa bar r requence of promotor
region , tRNA pay
TSO = A base sequence of escon region (deletion) D 7 , 3 bonds:
invadest
>
-
2 tumours in
demos de ·
Localized effect
Tastines
+ can
Epigenetics acetylation t mela a
+So ↑
metastesies :
memylation tacetylation ,
damage organs
langiogenesis
malignances
· -
can >
-
Breast cancers + destrogen
↑ oestrogen over
exposure to prolonged time , breat cancer rish
rmitoria i n d e st in sphase of i n ta
·
p
breaus
USING GENOME PROJECTS
genome = an
organisms set of DNA including all of it's genes & non-coding DNA
proteome : ine r u range of proteins an organism can produce
requencing projects have read the genome of a wide range of organisms' including humans
DNA
sequencing = ONLY WORKS WIL DNA FRAGMENTS : sequence of genome DNA must be separated into pagments
↑ each magment requenced separately + placed back in order >
-
entire genome
workingcusequencat
SIMPLER ORGANISMS = LeSS
Coding DNA :. Smaller genomes , allows us to work out proteome easily
Ibacteria/viruses =
sequencing of
DNA pamogenic bacteria/viruses used to identify + produce antigens t vaccines
COMPLEX ORGANISMS : genomes contain lots of non-coding DNA and regulatory genes so harder to fi nd proteome
HUMAN GENOME PROJECT :
Knowledge of human genes allows identification of mutant awes to diagnose + treat generic disorders
↑
ETHICS !:
it presence of diseased genes
> insure comparies charge more f
·
would you m a ke sensible life choices
·
arrest metal health
I
DNA sequencing memods are continuously updated
compared onlargesale
reautomated cheaper and ques
-
: a
,
-
~
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