About the time of , male genetic information from the sperm begins to be translated into protein products. This is used by some to determine when a mother and her conceptus become separate individuals.

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?

The negative impacts of nonnative species generally outweigh the positive impacts

When a human or animal consumes food, the carbon in that food is most likely to be converted into which of the following elements? a. carbon remains carbon b. nitrogen c. oxygen d. hydrogen