1. Which of the following is true of the evolution of cell membranes?
A) Cell membranes cannot evolve if proteins do not.
B) The evolution of cell membranes is driven by the evolution of glycoproteins and glycolipids.
C) An individual organism selects its preferred type of cell membrane for particular functions.
D) As populations of organisms evolve, different properties of their cell membranes are selected for or against.
E) Cell membranes have stopped evolving now that they are fluid mosaics.
2. Of the following functions, which is most important for the glycoproteins and glycolipids of animal cell membranes?
A) facilitated diffusion of molecules down their concentration gradients
B) a cell's ability to distinguish one type of neighboring cell from another
C) maintaining membrane fluidity at low temperatures
D) active transport of molecules against their concentration gradients
E) maintaining the integrity of a fluid mosaic membrane
3. Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?
A) CO2
B) an amino acid
C) K+
D) starch
E) glucose