The Lac Repressor Experiment

Question 1

E. Coli

Answer 1

Bacterium
Respires glucose but can use the lactose or glucose isn’t available.

If lactose is present the E. Coli makes an enzyme called B-galactosidase to digest it - it’s only present when lactose is present

If there’s no lactose it doesn’t waste energy making an Enzyme isn’t doesn’t need.

Question 2

What is B-galactosidase controller by ?

Answer 2

Transcription factor - the lac repressor

When there’s no lactose the lac reprowssor binds to the dna at start of the gene - stopping transition

When lactose is present it binds to the lac repressor stopping it binding to the DNA so gene is transcribed