57. About cell membrane, which of the following statements is NOT TRUE?
(A) Cell membranes are fluid mosaics of lipid and proteins, and the phospholipid bilayer is the basic building block of themembrane.
(B) Most of the phospholipids can shift about laterally in the plane of the membrane, but it is quite rare for phospholipidsto flip-flop transversely across the membrane because the hydrophilic part of the molecule must cross the hydrophobicinterior of the membrane.
(C) Phospholipids with saturated hydrocarbon tail pack more tightly, therefore decreasing membrane fluidity and viscosity.
(D) The presence of unsaturated hydrocarbon tails in phospholipids can enhance membrane fluidity, because unsaturatedhydrocarbon tails cannot pack together as closely as saturated carbon tails.
(E) The steroid cholesterol in the plasma membrane of animal cells can change membrane fluidity and this effect istemperature-dependent.