The cell membrane is a protective external layer that controls which substances are allowed to enter and leave the cell. The
cell membrane performs the same function in the cell as which
structure in the human body?
Blood
Skeleton
Skin
Hair

The diagram illustrates the activity of vesicles during a cellular process.

Which beat describes the brain stem

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?