2. Membranes are the barriers that separate the inside "living" part of a cell from the outside "non-living"
surroundings. Given that all new materials entering the cell must first cross the membrane, and given
that there is a limit to how much "stuff" can cross a unit area of membrane in a given time, explain how
this might set an upper limit on how big a single cell can be. In composing your answer, describe the
relation between cell size, cell volume, and cell membrane area (see your textbook for a details
discussion). (3 points)