HW10 key - Homework 10 1. What would be the result of an...

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Homework 10 1. What would be the result of an inactivation in the lactose operon by mutation of the following genes or sites: lacI , operator, promoter, lacZ and lacY ? Would the cell be able to utilize lactose as a sole carbon source? -A mutation in the lacI gene would cause a defective repressor. Either the repressor would not be able to bind the operator (constitutive expression of the lac operon) or the repressor would not be able to bind lactose (no expression of the lac operon). -A mutation in the operator would make it unable to bind the repressor and so you would see constitutive expression of the operon. -A mutation in the promoter would prevent operon expression. -A mutation in either lacZ or lacY would create non-functional B-galactosidase or permease. In either case, the cell will not be able to utilize lactose. 2. A new sugar, sugarose, induces the synthesis of two enzymes from the sug operon of E. coli . Some properties of mutations in genes of the operon affecting the appearance of these enzymes are as follows (+=enzyme induced normally, i.e., synthesized only in the presence of the inducer; C=synthesized continuously; 0=enzymes cannot be detected). Mutation of Enzyme 1 Enzyme 2 Gene A + 0 Gene B 0 + Gene C 0 0 Gene D C C The genes are adjacent in the order ABCD and the operon activity is analogous to that of the lac operon. Which of the following statements could not be true? Explain your answer. a. Gene
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This note was uploaded on 04/02/2008 for the course BIO 202 taught by Professor Howe during the Fall '06 term at New Mexico.

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HW10 key - Homework 10 1. What would be the result of an...

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