What is the function of the operator in the lac operon?
Binding site for RNA polymerase
Binding site for the repressor protein
Codes for the repressor protein
Codes for β-galactosidase
Related Questions
A mutant strain of E. coli is found where the repressor protein of the lac operon has lost its ability to bind to allolactose. In the presence of lactose, what would be the expected expression level of the lac operon genes in this mutant compared to a wild-type strain?
Higher than wild-type
Lower than wild-type
The same as wild-type
Completely absent
Where is the lac operon located?
Yeast
Humans
Plants
E. coli
Which of the following is a structural gene of lac-operon ?
Regulator gene
Operator gene
Promoter gene
Z gene
Which molecule acts as the inducer for the genes encoding β-galactosidase, permease, and transacetylase?
Glucose
Allolactose
Lactose
Galactose
In lac operon, when repressor protein binds to operator then
There is synthesis of -galactosidase enzyme
RNA polymerase cannot bind to the promoter
RNA polymerase binds to the promoter
There is mutation in i gene
An operon includes all of the following EXCEPT the region where RNA polymerase binds to initiate transcription. What is this region called?
Promoter
Operator
Structural genes
Regulator gene
Lactose transport into bacterial cells from the growth medium is facilitated by:
Permease
Diffusion
Transacetylase
β-galactosidase
In an environment containing both lactose and glucose, a mutation in the gene encoding adenylate cyclase renders it permanently inactive. What would be the primary consequence for lac operon expression?
Constitutive expression
Significantly reduced expression despite the presence of lactose
Expression levels similar to wild-type in the presence of only lactose
No change in expression compared to wild-type
In an E. coli strain, the i gene undergoes a mutation, and its product is unable to bind to the inducer molecule. If lactose is present in the growth medium, what will be the outcome?
The lac operon will remain repressed, and lactose metabolism will not occur.
The lac operon will be constitutively expressed, and lactose metabolism will occur.
The lac operon will be partially expressed, and lactose metabolism will be slow.
The repressor protein will bind to lactose, but transcription will not occur.
Lac I gene of Lac operon
lac permease
lac repressor
β-galactosidase
transacetylase
