The lac operon in E. coli controls the gene expression of the enzymes that digest lactose in the cell. In the presence of lactose, the lac operon will turn on and the genes will be expressed. Place the events of gene regulation by the lac operon in order of their occurrence, from the introduction of lactose to the environment to when the cell begins to digest lactose. A. The repressor is removed from the operator. B. RNA polymerase binds to the promoter region. C. Lactose enzyme genes are expressed by the operon. D. The regulatory gene expresses the repressor protein. E. The repressor is inactivated by lactose.
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First, the regulatory gene expresses the repressor protein (D). Show more…
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What is the function of the repressor in the E. coli lac operon? a. A repressor is a type of DNA sequence that is located outside the lac operon and expresses the protein that controls lactose gene expression. b. A repressor is a type of protein that inactivates the expression of the lac operon genes by binding to the DNA of the lac operon. c. A repressor is a type of DNA sequence which activates or inactivates the lac operon genes by acting as a protein binding site. d. A repressor is a type of DNA sequence that that activates the expression of the lactose genes by acting as an RNA polymerase binding site for the lac operon.
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Match each component of the lac operon in E. coli with its best description. lac I gene CAP + cAMP repressor protein lac permease (galactoside permease) beta-galactosidase promoter operon transporter that brings lactose codes for repressor protein set of genes that are transcribed sequence of DNA upstream from binds at operator site to block bind at activator site to activate enzyme that cleaves lactose
The lac operon consists of regulatory regions such as the promoter as well as the structural genes lacZ, lacY, and lacA, which code for proteins involved in lactose metabolism. What would be the outcome of a mutation in one of the structural genes of the lac operon? a. Mutation in structural genes will stop transcription. b. Mutated lacY will produce an abnormal $\beta$ galactosidase protein. c. Mutated lacA will produce a protein that will transfer an acetyl group to $\beta$ galactosidase. d. Transcription will continue but lactose will not be metabolized properly.
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