<prompt> Plasma membrane is freely permeable to -GlucoseUreaGlycerolAlcohol  <response>: Ans. is d i.e., Alcoholo As the major middle portion of membrane core of the membrane is formed by hydrophobic region of phospholipids, this portion is impermeable to the usual water-soluble substances, such as ions, glucose and urea.o Conversely, fat-soluble substances, such as oxygen, carbon dioxide, and alcohol, can penetrate this portion of the membrane with ease.o Permeability coefficient and permeability of some important molecules in increasing order of frequency are Na K Cl- Glucose Tryptophan Urea Glycerol Indole H2O. 