Chapter 11 Carbohydrates 8 14 What is the role of mannose 6-phosphate?What disease is caused by lack of this terminal sugar on glycoproteins? Ans:It acts as the marker that directs many lysozomal enzymes to their proper site.Without the modified mannose residue,the proteins are misdirected.For example,in I-cell disease, several enzymes are directed to blood and urine instead of the lysozomes.As a result, hydrolases required for glycosaminglycan and glycolipid degradation are missing,leading to deformity and retardation. Section:11.3 15 Why is it more difficult to determine the structure of the oligosaccharides,when compared to amino acid sequences？ Ans:Amino acids are linked through peptide bonds and the side chains vary in size,charge,and chemical properties.In contrast,sugars can be branched,and can have a or B linkages, which makes determining the attachment difficult.Furthermore,many sugars have the same or similar chemical formula,and similar chemical properties,making specific identification and linkage difficult. Section:11.3Chapter 11 Carbohydrates 8 14 What is the role of mannose 6-phosphate? What disease is caused by lack of this terminal sugar on glycoproteins? Ans: It acts as the marker that directs many lysozomal enzymes to their proper site. Without the modified mannose residue, the proteins are misdirected. For example, in I-cell disease, several enzymes are directed to blood and urine instead of the lysozomes. As a result, hydrolases required for glycosaminglycan and glycolipid degradation are missing, leading to deformity and retardation. Section: 11.3 15 Why is it more difficult to determine the structure of the oligosaccharides, when compared to amino acid sequences? Ans: Amino acids are linked through peptide bonds and the side chains vary in size, charge, and chemical properties. In contrast, sugars can be branched, and can have  or  linkages, which makes determining the attachment difficult. Furthermore, many sugars have the same or similar chemical formula, and similar chemical properties, making specific identification and linkage difficult. Section: 11.3