6.4 Kahoot - exam Flashcards
what are housekeeping genes
genes that are switched on all the time
another name for housekeeping genes is
constitutive genes
what is gene regulation
turning on and off genes
3 main levels of Gene Expression in prokaryotes
- post-translational control
- translational control
- transcriptional control
which level of Gene regulation is most common
transcription
what is an operon
a cluster of genes under the control of a promoter
operons are only found in…
prokaryotes
what is the purpose of a promoter region in transcription
binding sites for RNA polymerase
what is the function of the operator in an operon
it is the binding sites for the active repressor
what is the function of a repressor protein
turn off operons
where does a repressor protein bind
the operator region
inducible operons are turned ____ by default and need to be turned ____
are turned off by default and need to be turned on
inducible operons can be expressed by
removing the repressor from the operator
example of an inducible operon
lac operon
component of the lac operon
- structural genes
- the operator
- lac promoter
function of lac operon
to allow e. coli to digest lactose - makes lactase
what happens to the lac operon when no lactose is present
no transcription
what is an inducer
a protein that de-activates a repressor protein
in the lac operon, what causes the repressor to detach from the operon
lactose binds to the receptor causing it to detach
the repressor for the lac operon is ______ if lactose is present
inactive
for the lac operon, if lactose is absent then
repressor will bind to the operator and ultimately not breakdown lactose
for the lac operon if lactose is present then
the operon will be on
for the lac operon, lactose is the _____
inducer
what is catabolite activator protein (CAP)
A stimulator protein that makes transcription go faster
what must bind to the catabolite activator binding sites to increase transcription
CAP
how does the binding of CAP protein to the CAP site enhance transcription
it helps RNA polymerase bind to promoter
repressible operons
are usually turned on but can be turned off
an example of repressible operon
Trp operon
what is the purpose of trp operon
to make trytophan
when lots of tryptophan is present in a cell the trp operon is
repressed (OFF)
for the trp operon, trytophan is the _______
corepressor
the trp operon codes for enzyme that makes trytophan. How does tryptophan level influence trp expression
high levels of tryptophan leads to repression of the trp operon
how does tryptophan affect the repressor protein
- the shape of the repressor protein will change
- it will bind to the operator
- it will help prevent RNA polymerase from binding to the promoter
- it will bind to the operator
example of pre-transcriptional control in eukaryotes
chromatin accessibility
what is the term used for chromatin that is condensed
heterochromatin
for transcription to occur, what configuration must DNA be in
euchromatin
what is a type of DNA modification that makes it densely packed
methylation
function of transcription factors
Regulates gene expression by activating RNA polymerase
what are transcription factors
proteins that initiate and regulate the transcription of other genes
enhancer regions are sections of ___–
DNA
enhancer regions binds to what
activator proteins
post-transcriptional control includes…
- control of RNA splicing of introns
- control of RNA stability at its ends
- control of RNA shuttling out of nucleus
describe RNA interference
small segments of RNA bind to mRNA that prevents translation
what happens during RNA interference
miRNA/siRNAs prevent translation by binding and degrading mRNA
when miRNA./siRNA binds to mRNA, it forms…
RISC (RNA induced silencing complex
translational control involves…
the deterioration of mRNA
what is deadenylation
shortening of the 3’ poly-A tail
how does removing the poly-A tail (deadenylation) affect mRNA stability
it makes mRNA vulnerable to degradation by cellular enzymes
exoribonuclease function
degrades mRNA in cytoplasm that is missing cap and tail
post-translational modification of an amino acid chain
- methylation
- acetylation
- phosphorylation
what post-translational modification of an amino acid chain targets it for degradation
ubiquitination
what is epigenetics
change in gene activity without changes to genetic code
t/f epigenetic changes are reversible
true
a common epigenetic modification of DNA
methylation
how is infant DNA different than DNA of the elderly
higher methylated
what can epigenetics screening be useful for
detecting abnormal gene expression
what environmental factors can affect epigenetics affects unborn babies
- maternal drug use
- maternal stress
- maternal nutrition
t/f epigenetic changes and epigenetic markers can be passed on through generations
t
