Lecture 11
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Global regulation
Response to environmental signals by regulating expression of many differnt genes
Catabolite repression
Preference of a catabolite in a medium. ex) ecoli prefers gllucose
E. colis’ preference for glucose is called what?
The glucose effect Maximum growth rate Catabolic genes ofr other sugars are repressed
Only when all glucose is utilized are genes for ____ catabolism activated
lactose
Glucose exhausted leads to a ____ ____ in exponention growth
lag phase
Catabolite repressor is achieved by a
Transcriptional activator CRP CAP
Genes controlled by CRP require its binding at an activator site ____ of the ____ to be active
Upstream/promoter
CRP must first bind to ____ an inducer molecule to bind to an activator site
cAMP
cAMP is made from ____ by adeylate cyclase
ATP
Adenylate cyclase activity is ____ by glucose
Inhibited
As ____ is depleated cAMP levels ____ CRP becomes active
Glucose/increase
A shift down in nutrients or an energy deficiency may case a
Stringent response
Guanosine tetraphosphate and guanosin pentaphosphate are also called ____ and are the signal involved in global response
Alarmones
Binding of uncharged tRNA stalls ____
Ribosomes
RelA becomes active sythesizes ____
Pppgpp
r,tRNA synthesis ____ and amino acid biosythesis operons are selectively ____
decreased/activated
During stingent response DNA replication is ____ and cell envelope synthesis is ____
Inhibited/slowed
Stringent response also involved an ____ signal
energy
SpoT can degrade or sythesize
pppGpp
Synthesis is upregulated by shortage of ____ and ___
stress/energy
High temps or chemical stress can cause ____ of proteins ____ their activity
Denaturation/inhibiting
Imporoperly folded proteins are recognized by ____ and degraded
Proteases
Indiction of ____ ____ proteins helps deal with unfolded proteins
heat shock
Sigma factor RpoH activates transcription of heat shock proteins __ and __
Hsp70/Hsp60