Briefly describe the properties of lipid bilayers and how this dictates membrane permeability. Be sure to mention which types of molecules can and cannot pass through the lipid bilayer.

Lipid bilayer can be defined as a polar membrane, which composes two layers, made up of lipid molecules. It shows both hydrophobic (due to non-polar tails of lipid molecules) and hydrophilic (due to polar heads of lipid molecules) nature, and hence is known as of amphipathic nature.

Lipid bilayer shows selective permeability as not all molecules can cross the lipid bilayer. It can pass non-polar, small, uncharged molecules due to its hydrophobic core, such as oxygen, water, urea.

On the other hand, polar, large, or charged molecules, such as glucose, amino acids, and ions cannot pass through lipid bilayer. These molecules require transport proteins for their transport, which are embedded in lipid bilayer.

he lipid bilayer has unique properties. They are formed in sheet-like structures that contain both a hydrophilic and a hydrophobic moiety. The membrane is composed of lipids and proteins and sometimes even carbohydrates. There are two different membrane proteins in the lipid bilayer.