Question

The carbohydrates located in the extracellular matrix of animal cells function to add tensile strength and resiliency of connective tissue and for cell-cell communication. Which of the following represents molecules partially made from carbohydrates that are found in the extracellular matrix?

	a.	Chondroitin sulphate, collagen, keratan sulphate, heparin, and glycosphinolipids
	b.	Chondroitin sulphate, hyaluronan, keratan sulphate, heparin, and glycosphinolipids
	c.	Chondroitin sulphate, hyaluronan, integrin, heparin, and glycosphinolipids
	d.	Chondroitin sulphate, hyaluronan, keratan sulphate, fibronectin, and glycosphinolipids
	e.	Collagen, hyaluronan, integrin, heparin, and glycosphinolipids

Answer 1

b.

Chondroitin sulphate, hyaluronan, keratan sulphate, heparin, and glycosphinolipids

Glycosaminoglycans (GAGs) are classified into four groups. Heparin/heparan sulfate (HSGAGs) and chondroitin sulfate/dermatan sulfate (CSGAGs) are synthesized in the Golgi apparatus, where protein cores made in the rough endoplasmic reticulum are posttranslationally modified with O-linked glycosylations byglycosyltransferases forming proteoglycans. Keratan sulfate may modify core proteins through N-linked glycosylation or O-linked glycosylation of the proteoglycan. The fourth class of GAG, hyaluronic acid, is not synthesized by the Golgi, but rather by integral membrane synthases which immediately secrete the dynamically elongated disaccharide chain.