Exam 4: Cell Membranes, Transport, and Communication

Which of the following types of molecules could NOT easily diffuse across a plasma membrane?

Objects suspended in the extracellular fluid can cross the plasma membrane and enter a cell by all of the following processes,EXCEPT

Many hormones are large and hydrophilic.Where would you expect the receptor proteins for these hormones to be located?

In humans,hormonal communication between cells over long distances requires direct action by the brain.

As a biological process,osmosis

To coordinate the functions of specialized cells,those cells must be able to

Hydrophilic signaling molecules

Active carrier proteins are not found in the same cells as passive carrier proteins.

Signaling molecules can be "tagged" by attaching glow-in-the-dark molecules to them.After adding tagged signaling molecules to the fluid around several cells,you observe the cells with a microscope designed to see the glow-in-the-dark molecules.After a few minutes,you notice that the plasma membrane of some of the cells begins to glow.This observation indicates that some cells