please help! I have included my assignment that was marked! So confused Need hel
ID: 57742 • Letter: P
Question
please help! I have included my assignment that was marked! So confused Need help solving thank you in advance! A fictional bacterial operon is responsible for the production of the biosynthetic enzymes needed to make the theoretical amino acid Tisophane (Tis). In the wild? type condition, when Tis is present, no enzymes are made. In the absence of Tis, the enzymes are made. The operon is regulated by a separate gene, R, deletion of which causes loss of enzyme production, regardless of whether Tis is present. A second class of regulatory mutations has been identified and these map to a region (the RB site) near the promoter of the Tis operon; these so?called RB? mutations also block production of the enzymes, regardless of the availability of Tis. IS. a. Is the operon under positive or negative control? Justify your answer. b.Propose a model for regulation of the b. Propose a model for regulation of the operon which explains the lack of enzyme production in the presence of Tis in wildtype cells, the role of the R protein and the effects of the RB? mutations.Explanation / Answer
(a)
Based on the given data, the given operon is a repressible operon and it expresses under the absence of amino acid Tis. Positive regulation activates gene transcription, whereas the Negative regulation represses or inhibits the gene expression. So, the presence of Tis, deletion of regulatory gene (R) and mutation in R gene (RB site) represses the gene expression.
Thus, the operon is under “repressible negative regulation.”
(b)
This operon is similar to trp operon. Trp operon also regulate in the same manner. For example, if the tryptophan is present in the wild type cells, then the R gene expresses trp repressor protein. Now the excess of tryptophan binds to trp repressor protein and inhibit the gene expression by binding on operator gene (one of the regulatory gene).
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