This module introduces Overton's Rule in the context of understanding the permeability of molecules across the cell membrane. It is intended for an introductory biology audience.
This activity maps to the OpenStax biology textbook, 5.2 Passive Transport
Student Introduction: In the late 1800's, E. Overton discovered that substances that dissolve in lipids pass more easily into the cell than those that dissolve in water. This was some of the first evidence that cells were surrounded by a lipid membrane. The phospholipid membrane of cells can greatly modify the permeation of molecules into a cell. The membrane acts as a barrier to passive diffusion of water-soluble molecules. However, substances that dissolve in lipids pass more easily into the cell. The correlation between permeability and solubility in lipidly is appropriately named Overton's Rule.