Each of these four organisms began life as a single 2n cell. cells in each organisms divided and differentiated. probably the single most important process that ensured genetic continuity in all four organisms was dna

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?

Patient has just received an organ transplant which treatment would be most effective in preventing the patient’s body from

20 the compound al(nh3)2 has atoms of nitrogen.