In the lac operon, the repressor:a. binds to allolactose and becomes active, blocking lac gene expression. b. binds allolactose and binds to the promoter, and induces lac gene expression. c. binds to allolactose and becomes inactive, allowing lac gene expression to occur. d. binds to the promoter and blocks lac gene expression.

How many species of living things are alive on earth today? more than 1,000,000 none of these answers are correct 100-500 1,000 –500,000 o 500,000 -1,000,000

Question 1 of 102 pointswhich best describes adaptive radiation? oa. geographical isolation caused by an adaptationob. biodiversity resulting from few ancestorsoc. a decrease in the rate of speciationd. adaptations that organisms teach each other

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?