1. The diagram below illustrates the growth of E. coli cells on a medium containing small amounts of both glucose and lactose as the only C-sources.

(a) Which sugar (if any) is being utilized during time A? Time B? Time C?
(b) In which region(s) (A, B, C) is catabolite repression occurring?
(c) Is the intracellular concentration of cyclic AMP high or low in region A? In region C?
(d) Is lac repressor bound to DNA in region A? B? C?

2. How do eukaryotes differ from bacteria with respect to the following:
(a) size of RNA polymerase? __________________________
(b) rate of DNA replication? ___________________________
(c) frequency of introns? ____________________________
(d) coupling of transcription/translation? _________________
(e) organization of genes into operons? ___________________

Bonus Question: A cell mutates so that the gene coding for adenyl cyclase (the enzyme that converts ATP into cyclic AMP) is lost. Draw a graph similar to the figure in question 1 above that would accurately predict how this cell would behave in a medium containing both glucose and lactose.