Ahormone attaches to a target cell at a receptor protein. what do you know about this hormone?

select one:
a. it is a steroid hormone.
b. it will bind directly to dna.
c. it is able to pass through cell membranes.
d. it will not enter the nucleus.

What are some aquatic organisms that live in cold water temperatures?

The organelle pictured is found in cells of and is theorized to have once been an independent organism.

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?