CBSE Class 11-science Answered

1. Quasi fluid nature of lipid: It enables the lateral movement of proteins within the lipid bilayer.

 

2. Glycosylation is a critical function of the biosynthetic-secretory pathway in the endoplasmic reticulum (ER) and Golgi apparatus. Glycosylation is a commonly conserved process in the post translational protein modifications of eukaryotes and bacteria. However, glycosylation can be introduced by chemical modification in which carbohydrate molecule is conjugated to a protein, peptide, lipids etc.

 

   (i) Glycosylation of proteins: addition of carbohydrate to produce glycoproteins. The attachment of sugar moieties to proteins which is a post-translational modification.Sugar moieties on soluble proteins can be bound by specific receptors in the trans Golgi network to facilitate their delivery to the correct destination. These sugars can also act as ligands for receptors on the cell surface to mediate cell attachment or stimulate signal transduction pathways.

 

   (ii)Glycosidation of lipids: addition of oligosaccharides to produce glycolipids.