How is the plasma membrane of a cell organized?
question 15 options:

one layer of phospholipids, through which proteins freely move

one layer of phospholipids, which are laid out end-to-end, with a hydrophobic tail touching a hydrophilic head

two layers of phospholipids, each of which has its hydrophilic side turned inward

two layers of phospholipids, with their polar hydrophilic heads facing away from each other

Which of the following is not a characteristic of carnosaurs? a. long narrow skulls b. strong forelimbs c. horn projecting from their skulls d. none of the above

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?

Will ! a cell containing a 3% sucrose solution is placed into a beaker containing a 7% sucrose solution. assume the cell’s membrane is permeable to water, but not permeable to the sucrose. where will the water diffuse? explain.