What role does cAMP play in transcription of lac operon genes? What role does CAP play in transcription of lac operon genes?

The CAP binding site in the lac promoter is the location of positive regulation of gene expression for the operon. Identify what binds at this site to produce positive regulation, under what circumstances binding occurs, and how binding exerts a positive effect.

Is attenuation the product of an allosteric effect? Is attenuation the result of a transcriptional or a translational activity? Explain your answers.

Consider the transcription of genes of the lac operon under two conditions: (1) when both glucose and lactose are present and (2) when glucose is absent and lactose is present. Describe the comparative levels of transcription of lac operon genes under these conditions, and explain the molecular basis for the difference.

How would a cap⁻ mutation that produces an inactive CAP protein affect transcriptional control of the lac operon?

Explain the circumstances under which attenuation of operon gene expression is advantageous to a bacterial organism. Would you expect attenuation to be found in a single-celled eukaryote? In a multicelled eukaryote?

The trpL region contains four repeated DNA sequences that lead to the formation of stem-loop structures in mRNA. What are these stem-loop structures, and how do they affect transcription of the structural genes of the trp operon?