Lecture 37: Transcriptional Regulation 1. ##Please#identify#the#TRUE#statements#associated#with#cis8factors#that#regulate#transcription#(choose#all#that#apply)#a. Cis8factors#are#proteins#which#bind#regulatory#DNA#sequences#b. Promoters#and#repressors#are#both#examples#of#cis8factors#c. Enhancers*and*silencers*are*both*examples*of*cis5factors*d. Silencer#elements#are#cis8factors#that#bind#to#regions#of#the#DNA#known#as##repressors.###2. Helix8turn8helix,#B8zip,#zinc8finger#domains#are#all#examples#of#{DNA'binding-domains-(DBD)/effector-domains-(ED)}--3. Effector#Domains#participate#in#gene#activation#or#repression#by:#a. Recruiting#other#proteins#that#stabilize#or#inhibit#the#binding#of#the#polymerase#to#the#promoter#b. Interacting#with#polymerase#itself#to#stabilize#or#inhibit#the#polymerase#on#the#promoter#c. Interacting#with#mediator#proteins#that#bridge#to#the#polymerase#d. All*the*above*e. a.#and#b.#only.##4. In#transcription#factors#that#have#a#helix8turn8helix#domain,#both#helices#interact#with#bases#in#the#major#groove#to#make#stable#associations#with#the#DNA#True#False##5. Which#of#the#following#have#helix#turn#helix#domains?#a. CAP##b. The#lac#repressor#c. The#trp#repressor#d. Homeodomain#proteins#e. Estrogen#receptor#f. All#the#above#g. Only*a.*through*d.*h. Only#a.,#b.,#and#c.## #6. Of#the#transcription#factors#in#Q5,#which#are#examples#of#eukaryotic#factors?___d#and#e###7. Many#prokaryotic#genes#organized#into#transcription#units#by#function#–#those#genes#involved#in#the#same#pathway#are#regulated#by#one#promoter#region.#Such#polygenic#units#are#called#___operons__________________________________________##8. #In#the#repressor8inducer#complex#involved#in#the#regulation#of#this#transcriptional#unit,#what#are#the#identities#of#the#repressor#and#the#inducer?#a. Repressor:_______lac#repressor____________________________________________________#b. This#protein#is#transcribed#from#what#gene?___lac-I_____#c. Inducer:_______Allolactose_____________________________________________________#d. This#inducer#is#produced#from#what#disaccharide?____Lactose______#e. When#the#repressor#is#bound#by#the#inducer,#the#repressor’s#affinity#for#DNA#is##{increased/decreased}.##Lecture 37: Transcriptional Regulation 9. What#effect#does#the#presence#of#the#following#carbohydrates#in#the#growing#medium#have#on#the#regulation#of#transcription#of#the#lac-z,-lac-y-and-lac-a-genes.##a. Lactose#forms#the#inducer#allolatose,#which#through#binding#the#repressor#and#decreasing#its#affinity#for#DNA,#allows#transcription#of#the#lac#operon.#b. Glucose_When#glucose#is#present#in#the#medium,#the#CAP#protein#will#not#be#bound#to#activate#the#lac#operon#above#basal#levels#when#lactose#is#present.###(You#should#be#ready#to#interpret#whether#these#genes#in#the#lac#transcriptional#unit#wil l #b e#activated#or#repressed#when#given#specific#scenarios.)##10. #Where#does#the#repressor#bind#in#this#transcriptional#unit?#a. Promoter#b. Regulator#c. Operator*d. Enhancer##11. When#the#estrogen#receptor,#a#cell#surface#protein,#binds#estrogen,#it#is#endocytosed#and#then#the#receptor#travels#to#the#nucleus#to#bind#DNA.#True#False##12.
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