LIFE SCIENCE

Detailed explanation-1: -The hydrophobic core of the plasma membrane helps some materials move through the membrane, while it blocks the movement of others.

Detailed explanation-2: -The permeability of a membrane can be defined as the passive diffusion rate of permeated molecules across the biomembrane. It is unanimously accepted that permeability of any specific molecule depends mainly on charge number, polarity, size, and to some extent, to the molar mass of the molecule.

Detailed explanation-3: -Small nonpolar molecules, such as O2 and CO2, are soluble in the lipid bilayer and therefore can readily cross cell membranes. Small uncharged polar molecules, such as H2O, also can diffuse through membranes, but larger uncharged polar molecules, such as glucose, cannot.