Question

Determine whether the structure, location, and functions describe proteoglycans, peptidoglycan, glycoproteins, or glycolipids. GlcNAc is N-acetylglucosamine; MurNAc is N-acetylmuramic acid. Proteoglycans Peptidoglycan Glycoproteins Glycolipids Structure Location part of proteins at outer surface of plasma membrane, in extracellular matrix, and in blood Functions many functions, including cell adhesion strength for cell envelope Answer Bank glycosaminoglycan covalently joined to a protein at a Ser residue many functions, including acting as hormones bacterial cell wall extracellular matrix; some are integral membrane proteins outer membrane lipids of cells

Answer 1

	Proteoglycans	Peptidoglycan	Glycoproteins	Glycolipids
Structure	glycosaminoglycan covalently joined to a protein at a serine residue	The sugar component consists of alternating residues of β-(1,4) linked N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).	contain oligosaccharide chains (glycans) covalently attached to amino acid side-chains	Outer membrane -lipids of cells
Location	all connective tissues, extracellular matrix (ECM) and on the surfaces of many cell types.	Bacterial cell wall	Extracellular matrix, some are integral membrane proteins	found on the surface of all eukaryotic cell membranes, where they extend from the phospholipid bilayer into the extracellular environment
Function	as a lubricant or as a shock absorber.	gives strength to the outer structure of the organism.	important for cross-linking cells and proteins (e.g., collagen) to add strength and stability to a tissue	maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the connections that allow cells to connect to one another to form tissues.