The Lac Operon

Question 1

What are the parts to the lac operon?

Answer 1

regular gene - makes a TF that represses the transcription of structural genes

promotor region - where RNA polymerase binds to

operator

structural genes - lac Z, lac Y, lac A - code for enzymes

Question 2

What are regulator genes in the lac operon?

Answer 2

make transcription factors that control the expression of other genes

Question 3

What are structural genes?

Answer 3

make proteins that function in a cell e.g. enzymes

Question 4

How does the lac operon work with no lactose?

Answer 4

if lactose is not present

the lac repressor proteins binds to the operator

prevents RNA polymerase binding - no transcription

Question 5

How does the lac operon work with lactose?

Answer 5

lactose binds to the repressor protein which changes shape

removes it from the operator

RNA polymerase binds to the promotor region

structural genes are expressed - transcribed and trnslated

this then produces b-galatosidsae and lactose permase