Liposomes are being used for controlling the delivery of drugs to target cells. The formation of the bilayer is a spontaneous process. Danielli suggested this as a model for the biological membrane. Bilayer is not permeable by ions or polar molecules, except water. The membrane is a 2-dimensional fluid bilayer.
Biological membranes are asymmetric.
The outside and inside surfaces carry out different functional properties. Carbohydrate residues are on the extracellular side and may play a role in cellular recognition. 1. Spectrin . The major peripheral protein. Located on the cytoplasmic side.