The imprinting center is found in the promoter region of a non-coding gene called SNRPN. Based on the differences in modifications between the two copies of chromosome 15 in imprinted cells, which of the following statements about SNRPN would be true? A. The maternal copy of SNRPN is more highly expressed than the paternal copy.
B. The paternal copy of SNRPN is more highly expressed than the maternal copy.
C. Both copies of SNRPN are highly expressed.
D. Both copies of SNRPN are silenced.

Keeping in mind the life cycle of bacteriophages, consider the following problem: during the reproductive cycle of a temperate bacteriophage, the viral dna inserts into the bacterial chromosome where the resultant prophage behaves much like a trojan horse. it can remain quiescent, or it can become lytic and initiate a burst of progeny viruses. several operons maintain the prophage state by interacting with a repressor that keeps the lytic cycle in check. insults (ultraviolet light, for example) to the bacterial cell lead to a partial breakdown of the repressor, which in turn causes the production of enzymes involved in the lytic cycle. as stated in this simple form, would you consider this system of regulation to be operating under positive or negative control?