Where does a repressor bind an operon?

Consider the following statements and choose the correct answer:
1. The structural genes direct the synthesis of cellular proteins through messenger RNA (mRNA)
2. The promoter gene determines whether or not the structural genes are to be repressed by the repressor
3. The regulator gene directs the synthesis of a protein which may be an active repressor or an inactive repressor

A

1, 2 and 3 are true

B

Only 2 and 3 are true

C

Only 1 and 3 are true

D

Only 1 and 2 are true

In a mero-diploid you have one I- and one I+ Repressor gene in the two lac operons. I+ is wild type while I- is a mutant which produces a repressor that doesn’t bind. What would be the functionality of the diploid?

A

Function normally

B

Will be non-functional

C

May or may not function

D

Will have impaired functioning

Lac repressor dissociates from its operator when the repressor binds to ____________

A

Heat shock module

B

Promoter

C

Inducer

D

Catabolite activator site

A Lac repressor is a tetramer repressed when bound to the inducer. The trp repressor is a ____________________

A

Dimer inactivated when bound to the inducer

B

Dimer activated on inducer binding

C

Tetramer inactivated on inducer binding

D

Tetramer activated on inducer binding

What is the regulation of a lac operon by a repressor known as?

A

Neutral regulation

B

Positive regulation

C

Mixed regulation

D

Negative regulation

According to the repressor of lac operon which of the following are false?

A

It is the gene product of the regulatory gene

B

It binds to the promoter region

C

It blocks the transcription of structural genes

D

It combines with allolactose and thus does not bind to the operon

Which of the following acts as a co-repressor in tryptophan operon?

A

tryptophan

B

tyrosine

C

glucose

D

lactose

Repressor protein binds to which site in Lac Operon model?

A

Regulator

B

Promoter

C

Operator

D

Any of the above

Repressor molecules bind to __________

A

Operator

B

Promoter

C

Enhancer

D

Hormone response element

The capability of the repressor to bind the operator depends upon _____________

A

pH

B

conformation

C

temperature

D

moisture

Where does a repressor bind an operon?

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