👉 An excluding fluid, also known as an osmotic barrier or selective permeability membrane, is a type of biological membrane that selectively allows certain substances to pass through while blocking others. This membrane, typically found in cells like those of plants and animals, is composed of a phospholipid bilayer with embedded proteins. Due to its structure, it permits the passage of water and small, non-polar molecules like oxygen and carbon dioxide, but restricts larger ions, polar molecules, and other substances. This selective permeability is crucial for maintaining cellular homeostasis, regulating the internal environment by controlling what enters and exits the cell, and facilitating processes such as nutrient uptake and waste removal.
