Q.
Smaller, lipid soluble molecules diffuse faster through cell membrane, but the movement of hydrophilic substances is facilitated by certain transporters which are chemically
Particles which are lipid soluble (i.e., lipophilic or hydrophobic) can easily diffuse through the cell membrane as the lipid is a major constituent of the membrane. Where as hydrophilic substances {i.e., the substances which are soluble in water, e.g., glucose) do not pass through a biological membrane by simple diffusion. They are, therefore, transported across a cell membrane by facilitated diffusion {i.e., carrier mediated diffusion), which takes place with the help of certain transport proteins.