chapter 11 Flashcards
bacteria regulate transcription based on…
nutrients
lac operon order
I (separate gene for repressor)
P (promoter)
O (operator)
Z (beta galactosidase)
Y (permease)
A (transacytlase)
RNA polymerase binds to
the promoter (-35 to -10)
lac repressor
always expressed, binds to operator
lac repressor changes shape when bound to…
lactose, making it nonfunctional and turning on the lac operon pathway for transcription
allosteric transition
change of protein conformation that changes function
activator versus repressor
activator: pathway on until bound to by inducer
represser: pathway off until bound to by inducer
allosteric site
where the inducer binds
active site
where the repressor binds to operator
partially diploid
use modified plasmid to create partially diploid bacteria
cis acting
only regulates the genes linked to it
ex: operator
trans acting
can regulate other genes
ex: i (encodes repressor)
Z+ versus Z-
Z+ is dominant to Z-, these alleles determine if beta galactosidase is transcribed
O^c versus O^triangle
O^c repressor cannot bind (always on)
O^triangle no operator (always on)
O^c > O+
I+ versus I^s versus I-
I^s > I+ > I-
I^s is repressor can’t bind to lactose (always off)
I+ is wild type
I^- repressor is non functional (always on)
__ and __ complex activates trancription
cAMP and CAP
glucose regulates cAMP levels…
high glucose = cAMP
low glucose = low cAMP
cAMP levels
low cAMP -> little lac mRNA produced
high cAMP -> lots of mRNA produced
what does beta galactasidase do?
breaks lactose into glucose and galactose
positive versus negative regulation
positive regulation uses an activator
negative regulation uses a repressor
what does permease do?
transports lactose into the cell
