Which of the following statements regarding the structure and function of cell membranes is correct?

A  The phospholipid bilayer is arranged so that the hydrophilic heads of the phospholipid molecule face the extra- and intracellular fluids.

B  Peripheral membrane proteins function as channels associated with transport of ions through the membrane.

C  Some proteins integrated into the membrane serve as channels for the passage of nonpolar molecules through the membrane.

D  The plasma membrane is a layer of phospholipid molecules with their hyrophilic head groups in contact with the extracellular solution and the hydrophobic tail groups in contact with the intracellular solution.

E  Cholesterol molecules function to transport ions from one side of the plasma membrane to the other.