Chapter 7 Carbohydrates and Glycobiology

From the abbreviated name of the compound Gal(β1 → 4)Glc, we know that: A) C-4 of glucose is joined to C-1 of galactose by a glycosidic bond. B) the compound is a D-enantiomer. C) the galactose residue is at the reducing end. D) the glucose is in its pyranose form. E) the glucose residue is the β anomer.

A) C-4 of glucose is joined to C-1 of galactose by a glycosidic bond.

Which of the following techniques is not commonly used to study oligosaccharide structures? A) X-ray crystallography B) Matrix-assisted laser desorption/ionization mass spectroscopy (MALDI-MS) C) Nuclear magnetic resonance (NMR) D) Complete chemical synthesis E) Oligosaccharide microarrays

A) X-ray crystallography

In glycoproteins, the carbohydrate moiety is always attached through the amino acid residues: A) asparagine, serine, or threonine. B) aspartate or glutamate. C) glutamine or arginine. D) glycine, alanine, or aspartate. E) tryptophan, aspartate, or cysteine.

A) asparagine, serine, or threonine.

D-Glucose is called a reducing sugar because it undergoes an oxidation-reduction reaction at the anomeric carbon. One of the products of this reaction is: A) D-galactose. B) D-gluconate. C) D-glucuronate. D) D-ribose. E) muramic acid.

B) D-gluconate

Which of the following is an epimeric pair? A) D-glucose and D-glucosamine B) D-glucose and D-mannose C) D-glucose and L-glucose D) D-lactose and D-sucrose E) L-mannose and L-fructose

B) D-glucose and D-mannose

Which of the following monosaccharides is not an aldose? A) Erythrose B) Fructose C) Glucose D) Glyceraldehyde E) Ribose

B) Fructose

The basic structure of a proteoglycan consists of a core protein and a: A) glycolipid. B) glycosaminoglycan. C) lectin. D) lipopolysaccharide. E) peptidoglycan.

B) glycosaminoglycan.

Following complete hydrolysis of a sample of glycogen and a sample of cellulose, which of the following must be true? A) The glycogen sample is more soluble than the cellulose sample. B) The cellulose sample is more soluble than the glycogen sample. C) Both samples consist of a mixture of α-D-glucose and β-D-glucose. D) The glycogen sample has a higher ratio of α-D-glucose than the cellulose sample. E) The cellulose sample contains only β-D-glucose.

C) Both samples consist of a mixture of α-D-glucose and β-D-glucose

Which of the following statements about starch and glycogen is false? A) Amylose is unbranched; amylopectin and glycogen contain many (α1 → 6) branches. B) Both are homopolymers of glucose. C) Both serve primarily as structural elements in cell walls. D) Both starch and glycogen are stored intracellularly as insoluble granules. E) Glycogen is more extensively branched than starch.

C) Both serve primarily as structural elements in cell walls.

Which of the following monosaccharides is not a carboxylic acid? A) 6-Phospho-gluconate B) Gluconate C) Glucose D) Glucuronate E) Muramic acid

C) Glucose

Which of the following statements concerning sialic acid residues on glycoproteins is true? A) Sialic residues on erythrocytes are recognized by lectins, leading to removal of the erythrocytes. B) Sialic residues on ceruloplasmin are recognized by lectins, leading to removal of ceruloplasmin. C) Sialic residues are removed by neuraminidases. D) The anti-viral drug oseltamavir accelerates the removal of sialic acid residues. E) Both A and B above

C) Sialic residues are removed by neuraminidases.

Which of the following statements about heparan sulfate is not true? A) Sulfation of heparan sulfate to form NS domains is important for its role as an anti-coagulant. B) Heparan sulfate can promote protein-protein interactions via the NS domains. C) The secondary structure of heparan sulfate is completely random. D) The NA domains of heparan sulfate contain no sulfation. E) The core repeating structure of heparan sulfate is made up of alternating GlcNAc and GlcA.

C) The secondary structure of heparan sulfate is completely random.

To possess optical activity, a compound must be: A) a carbohydrate. B) a hexose. C) asymmetric. D) colored. E) D-glucose.

C) asymmetric

Hemoglobin glycation is a process where is attached to hemoglobin. A) glycerol; covalently B) glucose; enzymatically C) glucose; non-enzymatically D) N-acetyl-galactosamine; enzymatically E) galactose; non-enzymatically

C) glucose; non-enzymatically

The reference compound for naming D and L isomers of sugars is: A) fructose. B) glucose. C) glyceraldehyde. D) ribose. E) sucrose

C) glyceraldehyde.

When the linear form of glucose cyclizes, the product is a(n): A) anhydride. B) glycoside. C) hemiacetal. D) lactone. E) oligosaccharide.

C) hemiacetal.

Why is it surprising that the side chains of tryptophan residues in lectins can interact with sugars? A) Because the side chain of tryptophan is hydrophilic and sugars are hydrophobic B) Because the side chain of tryptophan is (-) charged and sugars are generally (+) charged or neutral C) Because the side chain of tryptophan can make hydrogen bonds and sugars cannot. D) Because the side chain of tryptophan is hydrophobic and sugars are generally hydrophilic E) None of the above

D) Because the side chain of tryptophan is hydrophobic and sugars are generally hydrophilic

When forming the disaccharide maltose from two glucose monosaccharides: A) water is eliminated. B) a hemiacetal is converted to an acetal. C) the resulting dissacharide is no longer a reducing sugar. D) Both A and B E) A, B, and C above

D) Both A and B

Which of the following statements about hydrogen bonding in glycogen and cellulose is true? A) Glycogen forms more internal H-bonds than cellulose. B) Extensive internal hydrogen bonding makes cellulose more water soluble than glycogen. C) Extensive hydrogen bonding with water makes cellulose more soluble than glycogen. D) Glycogen primarily forms hydrogen bonds within a single chain. E) The hydrogen bonding in cellulose favors a helical conformation.

D) Glycogen primarily forms hydrogen bonds within a single chain.

Which of the following is a heteropolysaccharide? A) Cellulose B) Chitin C) Glycogen D) Hyaluronate E) Starch

D) Hyaluronate

Which of the following is a dominant feature of the outer membrane of the cell wall of gram negative bacteria? A) Amylose B) Cellulose C) Glycoproteins D) Lipopolysaccharides E) Lipoproteins

D) Lipopolysaccharides

Which of the following is not a reason that it is difficult to study oligosaccharide composition from biological systems? A) Oligosaccharides are often branched. B) Oligosaccharides often have a high negative charge density. C) Oligosaccharides have a variety of linkages (e.g., α1→6 or β1→4). D) Oligosaccharides have too much conformational flexibility. E) There are no specific glycosidase enzymes that can be used to selectively digest oligosaccharides.

D) Oligosaccharides have too much conformational flexibility.

The biochemical property of lectins that is the basis for most of their biological effects is their ability to bind to: A) amphipathic molecules. B) hydrophobic molecules. C) specific lipids. D) specific oligosaccharides. E) specific peptides

D) specific oligosaccharides.

When two carbohydrates are epimers: A) one is a pyranose, the other a furanose. B) one is an aldose, the other a ketose. C) they differ in length by one carbon. D) they differ only in the configuration around one carbon atom. E) they rotate plane-polarized light in the same direction.

D) they differ only in the configuration around one carbon atom.

Which of following is an anomeric pair? A) D-glucose and D-fructose B) D-glucose and L-fructose C) D-glucose and L-glucose D) α-D-glucose and β-D-glucose E) α-D-glucose and β-L-glucose

D) α-D-glucose and β-D-glucose

Starch and glycogen are both polymers of: A) fructose. B) glucose1-phosphate. C) sucrose. D) α-D-glucose. E) β-D-glucose.

D) α-D-glucose.

Which of the following is not a reducing sugar? A) Fructose B) Glucose C) Glyceraldehyde D) Ribose E) Sucrose

E) Sucrose

Which of the following pairs is interconverted in the process of mutarotation? A) D-glucose and D-fructose B) D-glucose and D-galactose C) D-glucose and D-glucosamine D) D-glucose and L-glucose E) α-D-glucose and β-D-glucose

E) α-D-glucose and β-D-glucose