Bio 240 Topic 8 Regulation || WITH COMPLETE
SOLUTIONS.
two parts of holoenzyme (helper to RNA polymerase in transcription in bacteria) correct
answers core enzyme and sigma factor (determining correct location for transcription)
transcription in bacteria correct answers sigma factors bind to RNA pol core enzyme and
direct it to promoter
transcription prceeds
different sigma factors different genes
ways to stop transcription correct answers rho-dependent and rho independent
rho dependent correct answers rho protein follows RNA pol and removes it from DNA when
it reaches termination sequence
rho independent correct answers RNA produces hairpin loop (terminator loop) formation
causing RNA pol to disassociate from DNA
Shine Dalgarno sequence correct answers in translation in bacteria, ribosome biding site
which helps align machinery to correct starting location
allows mRNA to be polycistronic (multiple shine delgarno sequences and starting points so
more than one protein can be formed from one strand of mRNA)
regulation correct answers turning on and off different genes and proteins based on
environmental conditions and permits condition specific responses
examples of condition specific responses correct answers substrate specificity
metabolism and transport
sporulation
constitutive correct answers key cellular enzymes are always on "housekeeping genes"
ex) TCA cycle and ATP syntheses
Inducible genes correct answers only required at particular times
different levels of regulation correct answers transcription, translation, post-translation
Two ways to regulate proteins correct answers 1) covalent modification
2) allosteric modification
Allosteric regulation correct answers can be inhibition or activation depending on what
allosteric affecter molecule does at allosteric site
, when affecter molecule binds at allosteric site it causes conformation change in protein which
either allows substrate to bind which is activation, if it prevents substrate from binding it is
inhibition
ex) biosynthetic pathways of amino acids, you always need amino acids but in different
amounts
Covalent modification correct answers using different functional groups, adding them on
amino acid sequence ending up with different final conformations of enzyme which means
enzymes with different activity, can increase of stimulate activity or decrease or repress
ex) methylation, phosphorylation, chemotaxis
Operon correct answers series of structural genes and their transcriptional regulatory
elements , eukaryotes don't have operons
ex) lac operon
polysistronic correct answers producing more than one polypeptide
negative control correct answers protein controlling at operator, allosteric protein acts to
prevent mRNA synthesis, repression or induction
both induction and repression are negative control because they act on operator
positive control correct answers controlling at activator binding site, allosteric protein acts to
activate mRNA synthesis
ex) maltose catabolism in E. coli
weakly bind RNA polymerase, activator protein recruits polymerase to promoter
E. coli correct answers has regulating genes under one/both/neither
induction correct answers induction- deprepression of enzyme production in response to
signal, typically catabolic, no wasted energy
ex) lac operon
repression correct answers repression- inhibits transcription in response to signal (minority of
enzymes) typically anabolic enzymes
Effectors correct answers any molecule that effects protein conformation in association with
allosteric protein regulators
effector: co-inducers and co-activators correct answers turn on enzyme production, induce
and activate, turn on transcription and enzyme production only positive control
SOLUTIONS.
two parts of holoenzyme (helper to RNA polymerase in transcription in bacteria) correct
answers core enzyme and sigma factor (determining correct location for transcription)
transcription in bacteria correct answers sigma factors bind to RNA pol core enzyme and
direct it to promoter
transcription prceeds
different sigma factors different genes
ways to stop transcription correct answers rho-dependent and rho independent
rho dependent correct answers rho protein follows RNA pol and removes it from DNA when
it reaches termination sequence
rho independent correct answers RNA produces hairpin loop (terminator loop) formation
causing RNA pol to disassociate from DNA
Shine Dalgarno sequence correct answers in translation in bacteria, ribosome biding site
which helps align machinery to correct starting location
allows mRNA to be polycistronic (multiple shine delgarno sequences and starting points so
more than one protein can be formed from one strand of mRNA)
regulation correct answers turning on and off different genes and proteins based on
environmental conditions and permits condition specific responses
examples of condition specific responses correct answers substrate specificity
metabolism and transport
sporulation
constitutive correct answers key cellular enzymes are always on "housekeeping genes"
ex) TCA cycle and ATP syntheses
Inducible genes correct answers only required at particular times
different levels of regulation correct answers transcription, translation, post-translation
Two ways to regulate proteins correct answers 1) covalent modification
2) allosteric modification
Allosteric regulation correct answers can be inhibition or activation depending on what
allosteric affecter molecule does at allosteric site
, when affecter molecule binds at allosteric site it causes conformation change in protein which
either allows substrate to bind which is activation, if it prevents substrate from binding it is
inhibition
ex) biosynthetic pathways of amino acids, you always need amino acids but in different
amounts
Covalent modification correct answers using different functional groups, adding them on
amino acid sequence ending up with different final conformations of enzyme which means
enzymes with different activity, can increase of stimulate activity or decrease or repress
ex) methylation, phosphorylation, chemotaxis
Operon correct answers series of structural genes and their transcriptional regulatory
elements , eukaryotes don't have operons
ex) lac operon
polysistronic correct answers producing more than one polypeptide
negative control correct answers protein controlling at operator, allosteric protein acts to
prevent mRNA synthesis, repression or induction
both induction and repression are negative control because they act on operator
positive control correct answers controlling at activator binding site, allosteric protein acts to
activate mRNA synthesis
ex) maltose catabolism in E. coli
weakly bind RNA polymerase, activator protein recruits polymerase to promoter
E. coli correct answers has regulating genes under one/both/neither
induction correct answers induction- deprepression of enzyme production in response to
signal, typically catabolic, no wasted energy
ex) lac operon
repression correct answers repression- inhibits transcription in response to signal (minority of
enzymes) typically anabolic enzymes
Effectors correct answers any molecule that effects protein conformation in association with
allosteric protein regulators
effector: co-inducers and co-activators correct answers turn on enzyme production, induce
and activate, turn on transcription and enzyme production only positive control
