Question

Which type of molecule is more likely to quickly pass through a cellular membrane via simple diffion, polar or nonpolar? Why?

Answer 1

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. Have a good day:)