Which of the following types of molecules are most likely to pass directly through the cell membrane's phospholipid bi-layer utilizing simple diffusion?

Question

Question 4 options:

large, charged molecules

large, uncharged molecules

small, uncharged molecules

all of the above

Answer 1

The type of molecules most likely to pass directly through the cell membrane's phospholipid bilayer utilizing simple diffusion are small, uncharged molecules.

Simple diffusion occurs for small, nonpolar (or uncharged) molecules because they can easily move through the hydrophobic core of the lipid bilayer. Large or charged molecules typically require specialized transport mechanisms to cross the membrane.