25

Question 1

activation

Answer 1

inc of initiation

Question 2

repression

Answer 2

dec of inititaion

Question 3

constituitive gene expression level of expression

Answer 3

can be low or high

Question 4

most regulation of gene expression in bacteria

Answer 4

is transcriptional regulation

Question 5

what does regulation result from

Answer 5

intercations bw DNA binding proteins and their partner regulatory sequences

Question 6

elements of regulatory control

Answer 6

protomotors
terminators
ORFs
sogmal subunit of RNA pol
regulatory proteins or regulatory RNA

Question 7

amount of ORF in only one ORF reflects what

Answer 7

the strength of promoters and terminator doesnt affect matters much bc it is a single ORF

Question 8

what acts as regulators

Answer 8

ergulatory proteins or regulatory RNA

Question 9

regulatory control depends on what

Answer 9

there being two states for a regulatory system

Question 10

what are the two states for a regulatory system

Answer 10

regulatory protein does not bind to target sequence

regulatory proteins binds to a target sequenec

one turns genes on and other no so it functions as a swtich

Question 11

GTP dependant switch

Answer 11

eIF2
binding requires GTP and other has GDP bound and cannot bind initiator tRNA

Question 12

regulatory protein does not bind to target sequence does what do a gene

Answer 12

EITHER turns it on OR off depends on the gene

Question 13

where is an activator

Answer 13

upstream to the promoter

Question 14

where is a repressor

Answer 14

downstream to the promoter

Question 15

how are bacterial ggenes arranged

Answer 15

as operons- sequential arrangement of genes all experssed from THE SAME PROMOTER

Question 16

what happnes if the promoter is regulated in a bacterial gene (operons)

Answer 16

expression of all genes in the operon will be regulate in the same way
all ORFs activated or repressed to same degree

Question 17

proteins that decrease the level of transcription

Answer 17

repressors

Question 18

sequences organized by repressors are called

Answer 18

operators

Question 19

repressors and RNA polymerase

Answer 19

do not necessarily prevent binding of RNA polymerase

Question 20

where do repressors bind

Answer 20

slighly downstream of the RNA promoter binding site and prevent RNA pol from active transrciption

Question 21

proteins that inc transcription

Answer 21

activators

Question 22

where do activators bind DNA

Answer 22

upstream of RNA polymerase

Question 23

how do activators interact with RNA polymerase

Answer 23

interact with it in some way to help it bind more strongly to a promoter and thereby facilitate increased trasncription

Question 24

what is required for activator to interact with RNA pol

Answer 24

DNA looping may be necessary for regulatory proteins (activators) to interact with RNA pol

Question 25

what are other ways of influencing initiation of transrciption

Answer 25

spacer regulation sigma factor regulation inhibit open complexes

Question 26

what can change the way promoter elements are spacially organized relative to each other

Answer 26

MerR family regulators

Question 27

what do MerR family regulators do

Answer 27

what can change the way promoter elements are spacially organized relative to each other

Question 28

MerT promoter spacing

Answer 28

19bp between -35 and -10 elements which is not ideal for RNA pol

Question 29

what does MerR protein do

Answer 29

binds to the promoter changing its conformation so that it can resemble the more common bp spacing and puts the -10 and -35 on the same FACE of DNA

Question 30

what does MerR binding to the promoter lead to the sequence

Answer 30

makes promoter resemble the spacial geometry of the consensu promoter allows RNA pol to bind more readily so MerR protein activity enhacnces transcription

Question 31

how does MerR and RNA pol both bind

Answer 31

DNA bouble helix is like a cylinder so one protein can bind on one face and another can bind on another face

Question 32

6S RNA

Answer 32

184nt mimics the structure of DNA open complex binds to RNA pol during stationary phase so that RNA pol is not available for transcription

Question 33

6S RNA when is it transcribed

Answer 33

when [NTP] inc thereby destabilizing the complex and releasing 6S RNA