33. Which is a difference between integral membrane proteins and peripheral membrane proteins? (A) Integral membrane proteins contain mainly a-helices while peripheral membrane proteins contain mainly B-sheets. (B) Integral membrane proteins often contain carbohydrates on the inner surface while peripheral membrane proteins often contain carbohydrates on the outer surface. (C) Integral membrane proteins bind to the membrane using hydrophobic forces while peripheral membrane proteins bind to the membrane using hydrophilic forces. (D) Integral membrane proteins always span the entire membrane one time while peripheral membrane proteins are always located on one side of the membrane. (E) Integral and peripheral membrane proteins both contain transmembrane domain so they could associate with membranes.