lac operon

Inducible operon is normally turned off but can be turned on in the presence of

Inducer

Inactive repressor cannot:

bind to operator

Repressible operon normally turned on but can be turned off by ________.

Active repressor protein

Inactive Repressor protein can :

Not repress transcription without a co-repressor protein

What is a small molecule that binds to the repressor forming an active repressor protein?

Co-repressor

When is a repressible operon turned off ?

In the presence of a co-repressor molecule

Transcription turns off when the repressor protein is ____

Activated by the co-repressor

When this is present in the cell, it binds to the repressor and the repressor can no longer bind to the operator

Inducer

What is an inducible operon with 3 genes encoding enzymes that metabolize lactose for energy ?

Lac Operon

What does Lac I do :

Represses transcription when bound lac operator

When is the lac operon transcribed?

Only in the presence of lactose & the absence of glucose

The Lac Operon in E coli. Contains :

A single promoter & 3 genes required for lactose metabolism

The lac operon is an ________& _________.

Inducible; repressed

When lactose is not available to metabolize Lac I __________ the expression of genes in the lac operon

Represses

What binds to the lac operator & blocks RNA polymerase from initiating transcription?

Lac I

When lactose is readily available to metabolize it acts as an _______ molecule in the lac operon

Inducer

What deactivates Lac I ?

In the presence of lactose

When lac I is inactive what happens to the lac operon?

It can be transcribed

If E coli bacteria is grown in the presence of lactose what will happen to the repressor:

The repressor will not bind the operator allowing transcription of the lac operon genes