Question

which molecule will have the easiest time crossing a cell membrane by simple diffusion? a small non - polar molecule b small polar molecule c large non - polar molecule d large polar molecule

Explanation:

Cell membranes are composed of a lipid - bilayer. Non - polar molecules can dissolve in the lipid bilayer easily. Smaller molecules can pass through the membrane more readily than larger ones due to less steric hindrance. So, small non - polar molecules have the easiest time crossing by simple diffusion.

Answer:

A. small non - polar molecule