Final answer:
The statement is false; only small nonpolar molecules can easily diffuse through a lipid bilayer. Large, polar, or ionic molecules require transport proteins due to the hydrophobic nature of the bilayer's interior.
Step-by-step explanation:
The statement that 'given enough time, virtually any molecule will diffuse across a lipid bilayer' is false. The ability of a molecule to diffuse through the lipid bilayer depends heavily on its size and polarity. Small nonpolar molecules can easily diffuse as they are lipid-soluble and can interact favorably with the hydrophobic core of the lipid bilayer. Examples include oxygen (O₂) and carbon dioxide (CO₂). However, large polar or ionic molecules, which are hydrophilic, cannot easily cross due to being repelled by the hydrophobic interior of the bilayer. Instead, these molecules often require specific transport proteins to facilitate their movement across the membrane. These proteins provide a pathway that allows polar and charged substances to bypass the lipid bilayer.