Question

The cDNA for human insulin is cloned into an expression plasmid under control of the lac operon promoter/operator region. The plasmid is then transformed into E. coli. What would you need to add in order to generate the human insulin protein in this strain?

O glucose
O CAMP
O beta-galactosidase
O IPTG, a lactose analog
O none of these

Answer 1

To generate human insulin in E. coli using a plasmid with the cDNA for insulin, IPTG, a lactose analog, should be added to induce the lac operon, allowing the production of human insulin.

Step-by-step explanation:

To generate human insulin protein in E. coli that has been transformed with a plasmid containing the cDNA for human insulin under the control of the lac operon promoter/operator region, you would need to add IPTG, a lactose analog. IPTG acts as an inducer by binding to the repressor protein, thus preventing it from binding to the operator region. This allows RNA polymerase to bind to the promoter and initiate transcription of the insulin gene, leading to the production of human insulin.

It's important to note that while the presence of glucose can inhibit the lac operon, in this scenario we specifically add IPTG to induce the system regardless of the glucose level. CAMP is not needed in this context, as the lac operon can be artificially induced with IPTG. Similarly, neither glucose, beta-galactosidase, nor any other elements listed are necessary for the induction of insulin production in this genetically engineered system.