Question

question 2 of 10
the model shows the lac operon found in a prokaryotic cell.
the lac operon in e. coli
lac operon
1 2 3 genes for enzymes
4
enzyme enzyme enzyme
how is structure 2 involved in regulating the transcription of the lac operon?
a. structure 2 is the repressor, which prevents the operon from being transcribed.
b. structure 2 is the operator, which codes for the enzymes that break down lactose.
c. structure 2 is the promoter, where rna polymerase attaches and begins transcription.
d. structure 2 is the enhancer, which regulates the rate of transcription of the operon.

Explanation:

Step1: Recall lac operon structure

The lac operon has promoter, operator, etc.

Step2: Analyze each option

• A: Repressor is structure 4 (not 2).
• B: Operator (not 2) controls access. Genes code for enzymes.
• C: Promoter (structure 2) is where RNA polymerase binds.
• D: No enhancer in prokaryotic lac operon.

Answer:

C. Structure 2 is the promoter, where RNA polymerase attaches and begins transcription.