Question

Membrane carbohydrates:

1. What process results in glycolipids being located exclusively in the non-cytosolic monolayer of membranes?

2. In plasma membranes, what process results in the oligosaccharide residues of glycoproteins always found extending into the extracellular space?

3. What are some of the functions of the glycocalyx?

Answer 1

The glycolipids are present in the non cytosolic monolayer of membrane as they have to function in outer environment of the cell. These glycolipids consists of a saccharide group and a lipid moitey. The saccharide group is responsible for the linkage between cells. The processes they have to perform are cellular recognition for immune responses and for cell to cell interactions within the tissue, for initiating of some chemical pathways that are triggered when some molecule got attached with them on outer surface, for regulations, growth and apoptosis.

In plasma membrane, oligosaccharides are always present in the outer surface in extended firm because they are hydrophilic in nature and their formation also include condensation reaction, thus they are originated outside and present there. Moreover, they are responsible for some external reactions like recognition, initiating reactions and cell to cell linkages. They can also form N-glycosidic linkages.

Glycocalyx is a protective outer covering of the bacterium which is slimy and perform various functions. It acts like a protective layer and thus protect the bacterium from engulfment and thus resist phagocytosis. Thus layer also responsible for their adherence to the host cells or to form colonies for their better survival. This layer also causes virulence i.e. it is responsible for causing diseases to the host animal. Also this layer protects it from dehydration in harsh environmental conditions.