micro exam2 Flashcards
a gene that is always expressed
constitutive gene
a gene that is normally off, can be turned on
inducible
a gene that is normally on, but can be turned off
repressible
proteins that increase expression of a gene
activator proteins
proteins that decrease expression of a gene
respressior proteins
Activator and repressor proteins help____ to bind
RNA Polymerase
How does a small effector molecule(SEM) effect regulatory proteins?
SEM binds to regulatory proteins and change there confirmation…binding ablility
needs to be present in order for DNA replication to occur
Origin of replication
needs to be present in order for Transcription to occur
Promotor region
needs to be present in order for Translation to occur
start codon and Ribosome binding site
what is so important about promotors?
there presence regulates which genes are transcribed
“Prokaryotic immunity to viruses”
CRISPR/Cas
3 steps of the adaption stage of CRSPR/cas
1) cell survives
2) Adds new repeats
3) Adds new spacers
2 steps of intigration stage of CRSPR
1) transcription of the whole repeats/spacers region into one long strand of mRNA
2) Cas protein cuts into many 1repeat/1spacer regions called crRNA
- Inducible gene
- if a repressor protein is present but not an inducer present then___
no transcription
-if a repressor protein is present but so is an inducer molecule
transcriprion occures
if a repressor protein is present and a corepressor is present
no transcription
if an SEM is present and a repressor protein allows transcription then, the SEM was a____
inducer
if an SEM is present and a repressor protein blocks transcription then, the SEM was a____
corepressor
groups of genes controlled by one promotor
operon
if an SEM is present and a repressor protein blocks transcription then, the SEM was a corepressor what was the gene?
repressible (normally on)
if an SEM is present and a repressor protein allows transcription then, the SEM was a inducer then the gene was?
inducible(normally off)
If an inducer is present and so is an activator protein does transcription occur?
yes
If an inducer is present and so is an activator protein does transcription occur?
no
what is important about operons?
code for whole proteins instead of individual proteins
- saves time and resources
- more efficient then transcribing individual aminoacids
the repressor protein of the lactose operon
LacI
The Activator protein of the lactose operon
CAP
the gene name that codes for the repressor protein of lactose operon
italysized; “lacI”
-Lactose operon
if lactose is present and no glucose
High amounts of allolactose binds LacI prevents the (repressor from binding)Operator
- mRNA can be transcribed
- creating lactose enzymes
- Low cAMP, CAP is unbound from CAP site
where does LacI bind?
operator
where does CAP bind?
CAP site
relationship between glucose and cAMP
inverse
-high glucose and low lactose
low amounts of allolactose and low amounts of cAMP
- LacI(repressor) is bound
- CAP(activator) is unbound
- Lactose enzymes are not produced
are a mechanism to prematurely end transcription
Attenuator sequences
High tryptophane
- High amounts of tryptophan(corepressor)
- TrpR (repressor) binds
- No more trptophane being produces
Attenuator sequences require a ____region of RNA to be near an A:U rich region this causes____ ending transcription
- stem loop
- RNA Polymerase to fall off
cause RNA to pause
hairpins
if 2-3 hair pin forms then?
Ribosome pauses doesnt fall off
-Polymerase keeps going
which trp hairpins form depends on____
ribosome
minimum number of participants
quorum
bacteria use this to determin population density\
-chemical signal comunication
quorum sensing
population density effects___
gene expression
