Cell-recognition process

Fig. 3. Both adsorbed and transmembrane glycoproteins contribute to the formation of the cell glycocalyx. Once thought to function purely as a protective layer, cell surface oligosaccharides also participate in specific cell-recognition processes.

To say that a cell membrane is essentially a lipid bilayer would be an oversimplification. The basic structure of the lipid bilayer abounds with specific proteins contained within the membrane or attaehed to its surface. These serve as transport and recognition agents for the cell. Animal and some plant and fungal eells contain sugar residues on their surfaces. These have an important role in cell recognition processes, antigenie properties, and hor-... 

More than 40 structurally related sialic acids occur naturally where they play a number of roles. As covalently bound components of glycolipids and glycoproteins, they are intimately involved in cell recognition processes. 

The property of conformational restriction in polysaccharides make them candidates for being the initial self-ordering molecules of prebiotic evolution. This same property in the complex carbohydrate moiety of glycoproteins is the basis of carbohydrate-mediated information transfer through cell surface oligosaccharides interacting with each other or with lectin-like proteins in cell-cell recognition processes. 

Cell-surface carbohydrates mediate cell-recognition processes... 

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