Which of the following is most likely to cross the cell membrane by simple diffusion?
A) large proteins
B) small, charged ions
C) small, uncharged molecules
D) large, charged ions

Question

Quizplus · Accepted Answer

Small, uncharged molecules are most likely to cross the cell membrane by simple diffusion as they can move freely across the lipid bilayer. Large proteins and large, charged ions are too large to passively diffuse across the membrane, while small, charged ions experience electrostatic repulsion from the hydrophobic interior of the membrane, making it difficult for them to cross by simple diffusion.

Which of the Following Is Most Likely to Cross the Cell