Concept explainers
To determine: The
Introduction: A repressor molecule or protein prevents the RNA polymerase from binding to the promoter region and thus, prevents the expression of genes.
Explanation of Solution
The phenotype of a repressor mutation in which binding of DNA is prevented would be the expression of the genes which facilitate lactose
To determine: The phenotype of a repressor mutation that prevents DNA binding and an operator mutation that prevents repressor binding.
Introduction: In molecular biology, operator is a genetic sequence which is responsible for facilitating the transcribing proteins to bind to the DNA sequence being transcribed.
Explanation of Solution
Mutation in the operator or inducer that prevents the binding of the repressor would allow the operator to bing to the DNA all the time and the genes for lactose metabolism would not get expressed. This is because the RNA polymerase would bind to the DNA and transcription would proceed. This is in contrast to the phenotype expressed when mutation in the repressor would prevent transcription.
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Chapter 16 Solutions
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