T3M2 Flashcards
Operon end goal
the ability to express genes together, expressed as one big long mRNA sequence (polycistronic)
Polycistronic mRNA
a molecule that contains more than one protein encoding segment
Lactose operon is negatively regulated - negative cue
glucose is in the environment
cAMP levels will be ____ when glucose levels are high
low
What is cAMP?
a signaling molecule, more positive regulation of the lac operon, enhance gene operation, made from ATP
When glucose levels are low cAMP levels will be
high
CRP-cyclic AMP complex facilitates
the ability of RNA polymerase to bind to the lac promoter
More cAMP=
more positive regulation and less glucose!!
High glucose=
less cAMP, not binding as much to enhancer site
Is the lac operon ever fully off?
No, if it was fully off, 0 lac permease, run out of glucose and there is no cue for lactose to get in.
As E. coli cells transition from glucose to lactose
metabolism, there is a concomitant increase in
the amount of detectable beta-galactosidase and lactose permease proteins
beta-galactosidase and lactose permease proteins are not expressed until
glucose is fully depleted from the growth medium
lactose permease is
a transport protein that sits in the bacterial cell membrane and allows for the transport of lactose into the bacterial cells
The beta-galactosidase protein is
the cytoplasmically situated bacterial enzyme that cleaves the imported lactose into glucose and galactose
A key advantage to the organization of the prokaryotic genome is
groups of related genes with similar functions
can often be found clustered together into
operons - ability to control the transcription of the whole gene cluster as one unit