The extracellular matrix (ECM) is a complex combination of secreted proteins that is involved in holding cells and tissues together. The components of ECM form a network by binding to each other and communicate with cells by binding to adhesion receptors on the cell surface. ECM comprises mainly two classes of macromolecules, proteoglycans and very high molecular weight large proteins.
Which one of the following statements regard- ing ECM constituents is INCORRECT?
1
Proteoglycans are a subset of secreted or cell surface-attached glycoproteins containing covalently linked specialized polysaccharide chains called glycosamino- glycans (GAGs).
2
GAGS are long branched polymers of specific repeating disaccharides of sialic acid and glucose or galactose.
3
Major types of GAGS present in ECM are heparan sulphate, chondroitin sulphate, dermatan sulphate, keratan sulphate and hyaluronan.
4
Major types of large proteins present in ECM are collagen, laminin, elastin and fibronectin.
5
Question Not Attempted