Once inserted into the plasmid shown in Question 1, the gene 3021 is controlled by the lac operon. 

(i)   How does the lac operon exert transcriptional control?

(ii)  You plan to grow the bacteria transformed with pBPS-3021 in the presence of glucose initially and then, once all of the glucose is exhausted, add lactose to the medium.  Is this necessary?  Give a brief rationale for your response.

(10 marks)