Question

(regulatory gene, inducer, promoter, genes of an operon, repressor, operator, operon)1. A(n) ______is a stretch of DNA consisting of an operator, a promoter, and genes for a related set of proteins, usually making up an entire metabolic pathway.2. The ______ is/are arranged sequentially after the promoter.3. A(n) ________ is a specific nucleotide sequence in DNA that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place.4. A(n) _____ codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes.5. Regulatory proteins bind to the _______ to control expression of the operon.6. A(n) ______ is a protein that inhibits gene transcription. In prokaryotes, this protein binds to the DNA in or near the promoter.7. A(n) _______ is a specific small molecule that binds to a bacterial regulatory protein and changes its shape so that it cannot bind to an operator, thus switching an operon on.

Answer 1

Answer: An operon is described as a functioning unit of DNA that possesses cluster of genes, which are present under the control of single promoter. This means that all the genes of operon are transcribed at the same time to form a single polycistronic mRNA strand that codes for multiple proteins.

• An operon primarily consists of operator ( to which repressor protein binds, which is produced by regulatory gene and inhibits the expression of structural genes).

• promoter ( to which RNA polymerase binds and initiates transcription).

• structural genes/genes of an operon that are present downstream of promoter and are transcribed and translated to produce proteins.

Inducer is a protein molecule, binds to regulatory protein and brings change in its conformation so that it can no longer bind to an operator, thus switching on the operon.

Thus, the correct answer for blanks is-

1) operon

2) genes of an operon

3) promoter

4) regulatory gene

5) operator

6) repressor

7) inducer