Lac Operon Indicate whether each of the following statements about the lac opero

Question

Lac Operon

Indicate whether each of the following statements about the lac operon is true or false.

1. The lac operon consists of a coding region, which contains 3 genes that code for proteins needed to metabolize lactose, and a regulatory region, which regulates transcription of the coding region.  TrueFalse
2. In the lac operon, the 3 genes that code for proteins needed to metabolize lactose are transcribed as a unit, producing a single molecule of mRNA.  TrueFalse
3. Synthesis of the proteins needed to metabolize lactose is repressed by the presence of lactose.  TrueFalse
4. The lac operon is positively regulated by the lac repressor.  TrueFalse
5. When lactose is absent, the lac repressor binds to the promoter and blocks transcription of the genes that code for proteins needed to metabolize lactose.  TrueFalse
6. When lactose is present, the lac repressor cannot bind to the operator; therefore, RNA polymerase can transcribe the genes that code for proteins needed to metabolize lactose.  TrueFalse
7. The coding region of the lac operon is transcribed when the CAP-cAMP complex is bound to the CAP binding site and the lac repressor is bound to the operator.  TrueFalse
8. The presence of glucose blocks induction of the lac operon.  TrueFalse
9. CAP alone does not bind to DNA, but binding of cAMP to CAP alters its conformation so that it can bind to DNA.  TrueFalse
10. When the level of glucose is high, cAMP is abundant and binds to CAP.  TrueFalse
11. When the CAP-cAMP complex binds to the CAP binding site, this bends the DNA which blocks binding of RNA polymerase to the promoter.  TrueFalse

Explanation / Answer

Answer 1)TRUE

Lac operon consists of three genes in the coding region, namely:

Lac a - codes for transacetylase

Lac y- codes for lactose permease

Lac y- codes for beta galactosidase

Ans 2-True

Ans3-false

Ans4- false

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