bio 105 - lac operon

What part of a gene initiates transcription?

The promoter

In normal conditions (low lactose) what level if the lac-operon protein expression would you expect to see in an average e coli cell?

Low

When protein changes its shape because something has bound to it, the process is called...

Allosteric regulation

When lactose is present, it...

Binds to the repressor

When lactose is bound to the repressor...

The repressor can no longer bind to the promoter

When lactose is present, does the repressor bind?

No, the repressor does not bind

When lactose is present, what is the status of the lactose operon?

The lac operon is "on" and being transcribed

When lactose is present in the environment, the lactose repressor _____ its DNA binding ability. This allows for what?

Loses. This allows RNA polymerase to bind to the promoter and transcribe the lac operon.

When the lac operon is being transcribed...

...the cell produces machinery to metabolize (break down) additional lactose quickly and effectively.

constitutive genes

genes that are expressed all the time

Are lac repressors constitutively expressed? What does this mean?

Yes! The lacl protein is always being produced.