Membrane Structure Membrane Structure Cell membranes are essential to the life of a cell. Inside the cell, the membranes of the organelles interface them with the cytosol and carry out specific functions for each organelle.
Membranes are dynamic, fluid structures.
Protein molecules are embedded into the lipid bilayer and perform most of the other membrane functions, i.e., transport, ATP synthesis, etc. Both the lipid and protein composition of the two sides of a membrane are very different, thus, membranes are asymmetrical. The bilayer structure is due to the special properties of lipid molecules, which cause them to assemble spontaneously into bilayes even in simple artificial conditions. In other words, they have both a hydrophilic and a hydrophobic end. The most abundant are the phospholipids.