the __________ regulates what passes into and out of the cell.
Fluid-mosaic model. 1  Plasma membrane consists of a phospholipid bilayer studded with proteins, polysaccharides, lipids. 2  The lipid bilayer is semipermeable Regulates passage of substances into and out of the cell. H2O and some small, uncharged, molecules (O2, CO2) can pass through.