Occupational and Environmental Health: Recognizing and Preventing Disease and Injury - Multiple Choice Questions - Learn & Prevent

Which type of molecules generally passes through membranes more quickly?

1. Large, polar molecules

2. Small, nonpolar molecules

3. Large, nonpolar molecules

4. Small, polar molecules

The correct answer is: Small, nonpolar molecules

This is because small, nonpolar molecules are typically uncharged and can easily pass through the hydrophobic lipid bilayer of a cell membrane. Large, polar molecules, on the other hand, are often charged and may be repelled by the nonpolar region of the membrane. Similarly, large, nonpolar molecules may struggle to pass through the small pores in the membrane, whereas small, polar molecules may be unable to pass through due to their polarity. Overall, small, nonpolar molecules have the best combination of size and charge to easily pass through cell membranes.