Specialized Cells Three students made different statements about cells and the human body. This is what they said:

Student A: “The human body is made up entirely of a collection of trillions of cells and things made from cells.”

Student B: “The human body is surrounded by an outer covering. Inside this covering the body is filled in with cells and things made from cells.”

Student C: “The human body is a collection of trillions of cells and things made from cells contained inside an outer covering and inner coverings that contain organs.”

Which student do you think best describes the human body?



Explain your thinking

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?