You have worked on a gene for eternal youth for the past ten years and discovered it is not the needed expression of a gene at all but the presence of an ""old age"" gene that needs to be knocked out to get to the ""fountain of youth."" what would be the outcome if the procedure used to make the gene-targeted (knock-out) mouse for the foy (fountain of youth knock out mouse) was embryonic lethal? would this still be a useful model to study?

Forces that are equal in strength but opposite in direction are a.) balanced b.) unbalanced c.) always result in motion d.) do not exist

Why would a drug that damages capsids treat a viral infection? a. capsids prevent the lytic cycle from beginning. b. transduction requires a capsid. c. viruses use capsids to increase genetic variation. d. capsids provide protection for viruses.

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?