L9 Regulation of gene expression

Question 1

How are metabolic pathways regulated at the protein level

Answer 1

feedback inhibition

Question 2

How are metabolic pathways regulated at the gene level

Answer 2

control the production of an enzyme by regulating gene transcription

Question 4

how are metabolic pathways regulated at the protein level

Answer 4

feedback inhibition

Question 5

how are metabolic pathways regulated at the gene level

Answer 5

ctrl of the production of an enzyme by regulating gene transcription

Question 6

what is feedback inhibition

Answer 6

Feedback inhibition involves the use of a reaction product to regulate its own further production. The cell responds to an abundance of the products by slowing down production during anabolic or catabolic reactions. Such reaction products may inhibit the enzymes that catalyzed their production

Question 7

what are prokaryotic genes organized into

Answer 7

operons

Question 8

what does operon ctrl

Answer 8

gene expression in bacteria

Question 9

what does operon contain

Answer 9

gene that codes for proteins that function in same metabolic pathway

Question 10

what do the genes in operon code for

Answer 10

proteins that function in same metabolic pathway

Question 11

what is operon composed of

Answer 11

1- promoter
2- genes that will be ctrld

Question 12

what is the promoter of the operon

Answer 12

• contains operator
• acts as an on/off switch

Question 13

the genes that will be controlled in the operon are the genes of what

Answer 13

genes that code for all enzymes in same pathway

Question 14

the genes in the operon, how are they transcribed

Answer 14

as a single mRNA, they are clustered and work together. they are controlled by the promoter

Question 15

the mRNA produced by operon contains what

Answer 15

start/stop codons for each polypeptide

Question 16

when an operon is ON:
- RNA polymerase…
transcription…
translation…

Answer 16

• RNA polymerase binds to promoter
• transcription occurs: all genes transcribed as 1 long mRNA
• translation occurs: production of all polypeptides (enzymes) in pathway

Question 17

when operon is off: - - what happens to operator
- RNA pol…
transcription…

Answer 17

• repressor protein binds to operator
• rna pol can’t bind to promoter
• transcription blocked

Question 18

advantage of operon existing in 2 states

Answer 18

all enzymes needed in metabolic pathway produced or turned off AT ONCE

Question 19

where is the regulatory gene

Answer 19

upstream of operon promoter

Question 20

what is the repressor protein produced by

Answer 20

regulatory gene

Question 21

when is regulatory gene transcribed, and what does this mean for repressor prot

Answer 21

always transcribed= repressor protein always produced

Question 22

the binding of a repressor to operator is —–

Answer 22

reversible

Question 23

what kind of protein is repressor protein

Answer 23

allosteric protein, meaning having allosteric site

Question 24

when the protein is in active conformation what does it do

Answer 24

binds to operator

Question 25

when the protein is in inactive conformation what does it do

Answer 25

does not bind to operator

Question 26

what is the activity of repressor protein dependant on

Answer 26

metabolites in cell (ex. tryptophan, allolactose)