Which of the following best describes one way electron microscopes and light microscopes differ in structure? a) light microscopes use vacuum tubes instead of electron beams to concentrate light on the stage b) electron microscopes use an infrared light source instead of a regular light to display images c) electron microscopes use a beam of electrons instead of light to magnify images d) light microscopes use lamps instead of electric cables as a power source

Pepsin is an enzyme in the stomach that breaks polypeptides into amino acids. pepsin functions best at a ph of around 1.5. what would be the most likely result if the ph of the stomach were increased to 5

Rotenone is an insecticide that is toxic

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?