You have just isolated a new drug that has only one effect on cell metabolism; it totally inhibits the breakdown of pre-rRNA to ribosomal RNA. After treating a culture of mammalian cells with this drug, you give the cells [3H]uridine for two minutes, and then grow the cells in the presence of the drug in unlabeled medium for four hours before extracting the RNA and centrifuging it through a sucrose gradient. Required:
Draw the curves you would obtain by plotting both absorbance at 260 nm and radioactivity against the fraction number of the gradient.

Akrabby blind whale has married pearl who has normal vision. oneof their two sons is also colorblind. what arr the genotypes of the parents?

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?

This is a situation in which genes are attached to an organism's sex chromosomes; the sex of an organism influences the expression of a gene.