The trp L region contains four repeated DNA sequences that lead to the formation of stem-loop ...

1.  The trp L 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?



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



3. Describe how ara C protein functions as both a positive and negative regulator of ara (arabinose) operon transcription.