TLS Online TPP Program

#Question id: 1369


The following statements are made with reference to characteristics of glycosaminoglycans and proteoglycans, which are major constituents of extracellular matrix. Which one of them is incorrect?

#Unit 4. Cell Communication and Cell Signaling
  1. Glycosaminoglycans are long linear polymers of specific repeating disaccharides. Usually one sugar is either a uronic acid or d-galactose; the other sugar is N-acetylglucosamine or N-acetylgalactosamine.

  2. Proteoglycan core proteins are synthesized in the endoplasmic reticulum, and the GAG chains are assembled on and covalently attached to these cores in the Golgi complex.

  3. All GAG chains are elongated by the alternating addition of sugar monomers to form the disaccharide repeats characteristic of a particular GAG; the chains are often modified subsequently by the covalent linkage of small molecules such as sulfate.

  4. The ratio of polysaccharide to protein in all proteoglycans is much lower than that in most other glycoproteins.

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