[Lec 7] Key Terms: Regulation of Prokaryotic Transcription

Question 1

basal levels

Answer 1

neither activated nor repressed

Question 2

repressed

Answer 2

regulation occurs through negative control

Question 3

activation

Answer 3

regulation occurs through positive control

Question 4

combination

Answer 4

both positive and negative control

Question 5

repressors

Answer 5

block transcription

Question 6

activators

Answer 6

enhance transcription

Question 7

allosteric repressor

Answer 7

induces a conformation change that prevents polymerase from leaving promoter

Question 8

allosteric activators

Answer 8

induces a conformation change; something other than making more mRNA and recruiting mRNAs

Question 9

DNA binding domain

Answer 9

determines what sequences are recognized

Question 10

activation domain

Answer 10

interact with RNA polymerase or other transcription factors to stimulate transcription

Question 11

operons

Answer 11

contains many genes under the control of one promoter; regions of DNA that interact with regulatory proteins

Question 12

coordinate control

Answer 12

genes encoding enzymes in a common pathway can all be induced simulataneously

Question 13

beta-galactosidase

Answer 13

cleaves lactose into galactose and glucose

Question 14

lactose permease

Answer 14

transports lactose into the cell

Question 15

lac operon

Answer 15

encodes lactose metabolism machinery

Question 16

Negative control of lac operon

Answer 16

lac repressor expression in absence of lactose; when allolactose binds, the repressor is derepressed

Question 17

Positive control of lac operon

Answer 17

cap activates expression in absence of glucose

Question 18

AraC

Answer 18

acts as both a repressor and activator; works together with CAP-cAMP to stimulate RNA polymerase binding; looping prevents activation