What is the Molecule stopped by cell membrane?

Answer 1

The cell membrane primarily acts as a barrier to large, polar, and charged molecules, which cannot easily pass through its lipid bilayer. Examples of such molecules include glucose and ions like sodium and potassium. These substances typically require specific transport proteins or channels to facilitate their movement across the membrane. In contrast, small nonpolar molecules, such as oxygen and carbon dioxide, can diffuse freely through the membrane.