Exam 15: Regulation of Gene Expression

Approximately 5 percent of the cytosine residues are methylated in the genome of any given eukaryote. In what way is DNA methylation related to genetic regulation?

Describe the function and general nature of promoters in eukaryotes.

Certain mutations in the regulator gene of the lac system in E. coli result in maximal synthesis of the Lac proteins (fi -galactosidase, etc.) even in the absence of the inducer (lactose). Provide an explanation for this observation.

Alternative RNA splicing is a method that apparently evolved for the production of many different polypeptides from the same pre -mRNA. Provide an example of alternative splicing.