Prokaryotic Transcription

Question 1

What is a promoter?

Answer 1

The site where RNA Polymerase binds to the DNA prior to staying transcription.

Question 2

Components of the operon.

Answer 2

Promoter, Operator, Structural Genes

Question 3

What component contains the binding site for the transcriptional regulator?

Answer 3

Operator

Question 4

Which protein has a high affinity for the operator?

Answer 4

Repressor protein

Question 5

What does an effector molecule do? Provide an example.

Answer 5

Causes a conformational change in shape and activity.

Tryptophan.

Question 6

What is allosteric control?

Answer 6

The regulation of an enzyme by binding an effector molecule at a site other than the enzyme’s active site.

Question 7

What happens in allosteric inhibition?

Answer 7

The inhibitor alters the active site preventing the substrate from binding to the enzyme.

Question 8

What happens in allosteric activation?

Answer 8

The activator alters the active site in a favorable way for the substrate making it easier to bind to the active site of the enzyme.

Question 9

Explain negative regulation and its two systems.

Answer 9

Bound repression protein prevents transcription. Negative regulation involves a repressor. It has an inducible system and a repressible system.

Question 10

Negative Regulation Inducible System

Answer 10

Gene OFF: (+) Operator Bound and (-) Ligand
Gene ON: (-) Operator Bound and (+) Ligand

Hint: Gene OFF Status in Negative Regulation Systems WILL ALWAYS BE OPERATOR BOUND (+)

Question 11

Negative Regulation Repressible System

Answer 11

Gene OFF: (+) Operator Bound and (+) Ligand
Gene ON: (-) Operator Bound and (-) Ligand

Hint: Operator Bound and Ligand statuses will be the same in negative regulation repressible systems. (+)(+) or (-)(-).