Chapter 8
The sialic acids A. are important constituents of glycoproteins and glycolipids B. are N-acetyl glucosamine derivatives C. incorporate a succinic acid derivative D. all of the above E. none of the above
A
Which of the following polysaccharides cannot be digested by mammalian salivary, gastric, or pancreatic enzymes? A. cellulose B. amylopectin C. amylose D. glycogen E. starch
A
Uronic acid is the result of oxidation of the primary ... group of an aldose.
Alcohol
Is glucose and aldose or a ketose?
Aldose
... is an enzyme found in saliva that hydrolyzes the α(1→4) glycosidic bond in starch.
Amylase
Both α (1 → 4) and α (1→6) bonds can be found in the plant product ...
Amylopectin
Both α(1→4) and α(1→6) bonds can be found in the plant product ...
Amylopectin
The monosaccharides α-D-galactose and β-D-galactose are ...
Anomers
D-fructose has 3 asymmetric carbon atoms. How many epimers does it have in the D-configuration. A. 0 B. 2 C. 3 D. 6
B
D-glucose has 4 asymmetric carbon atoms. How many epimers does it have in the D-configuration? A. 0 B. 3 C. 4 D. 8
B
How many stereoisomers are possible for a ketopentose such as ribulose? A. 2 B. 4 C. 8 D. 16 E. 32
B
In terms of structure, what is the main difference between α-amylose and cellulose? A. Cellulose is linear, but α-amylose is branched. B. Cellulose is formed by β-(1→4) glycosidic bonds, but α-amylose is formed by α-(1→4) glycosidic bonds. C. Cellulose is branched, but α-amylose is a linear polymer. D. Cellulose is a linear polymer of D-glucose, but α-amylose is a linear polymer of D-allose.
B
In which way are saccharides similar to amino acids? A. They are formed from three elements, C, H, and O. B. They can be joined covalently to form polymers. C. Their polymers are not made from a template. D. They do not form polymers capable of catalysis.
B
The transformation of a monosaccharide into its ... occurs easily and does not require the assistance of a catalyst. A. epimer B. anomer C. sugar alcohol D. diastereomer E. none of the above
B
Unlike proteins and oligonucleotides, polysaccharides A. are readily metabolized in the absence of specialized enzymes. B. often have branched structures. C. are achiral. D. are always very water soluble. E. are components of every known living organism.
B
Which of the following does not accurately describe glycosylation sites of proteins? A. Asn, Ser, or Thr residues B. Buried residues inside protein C. In loops or turns D. On the surfaces of proteins
B
Which polysaccharide is found in a helically coiled conformation? A. chitin B. α-amylose C. cellulose D. lignin E. none of the above
B
Which statement about stereoisomers is false? A. D- and L-isomers are mirror images of each other. B. Epimers can interconvert rapidly in solution. C. Anomers freely interconvert in solution through a linear intermediate. D. Some hexoses can interconvert between pyranose and furanose forms.
B
A saccharide that has free aldehyde group is called a(n) ... A. ketose B. non-reducing sugar C. reducing sugar D. aldohexose E. alditol
C
Bacterial cell walls are constructed of ... A. pectin B. chondroitin sulfate chains C. peptidoglycans D. heparin E. all of the above
C
Cellulose is A. a linear copolymer of glucose and galactose B. a branched polymer of glucose C. a linear polymer of glucose with β(1→4) linkages D. a linear polymer of glucose with α(1→4) linkages E. sometimes called starch
C
How many stereoisomers are possible for an aldopentose such as ribose? A. 2 B. 4 C. 8 D. 16 E. 32
C
The bonding of alcohols to the anomeric center of a carbohydrate results in the formation of a(n) ... bond. A. anomeric B. amide C. glycosidic D. ester E. hydrogen
C
Which bond is not considered a glycosidic bond? A. Between an anomeric carbon and the nitogen of acetylamine. B. Between the oxygen of one anomeric carbon and the carbon of another anomeric carbon. C. Between the oxygen of carbon 3 of ribose and a phosphate. D. Between an anomeric carbon and an alcohol oxygen.
C
Which of the following sugars is not a reducing sugar? A. glucose B. ribose C. sucrose D. starch E. galactose
C
... is the primary structural component of the exoskeleton of many invertebrates, and is also found in the cell walls of most fungi and many algae.
Chitin
Artificial sweeteners are popular with dieters because A. they cannot be readily metabolized. B. they are peptides and provide important amino acids. C. they have fewer calories than sucrose. D. they are much sweeter than sucrose. E. all of the above
D
At equilibrium in solution, D-glucose consists of a mixture of its anomers. Which statement most accurately describes the solution? A. The solution consists of approximately equal amounts of the α- and β-anomers. B. The straight-chain form is present in high concentration. C. The α-anomer is more stable and is slightly preferred over the β-anomer. D. The β-anomer predominates over the α-anomer by a ratio of approximately 2:1. E. None of the above.
D
Chitin differs from cellulose due to A. inversion of configuration at the anomeric carbon. B. sulfonation of the C2 OH group. C. a much greater prevalence of branching. D. replacement of the C2 OH group by an acetamido group. E. replacement of the C6 OH group by an amino group.
D
Hyaluronic acids would not be good energy storage polysaccharides because A. enzymes cannot cleave β(1→4) linkages. B. hyaluronic acids are always short polymers (<250 units). C. hyaluronic acids are too insoluble. D. solutions of hyaluronic acids have a very large osmotic pressure. E. none of the above
D
In terms of structure, which of the following is the main difference between cellulose and chitin? A. Cellulose is formed by β-(1->4) glycosidic bonds, while chitin is formed by -(1->4) glycosidic bonds. B. Cellulose is neutral, but chitin is negatively charged. C. Cellulose is linear, but chitin is branched. D. Cellulose is a linear polymer of D-glucose, but chitin is a linear polymer of N-acetyl-D-glucosamine.
D
O-linked oligosaccharides are commonly attached to the oxygen of ... A. ribose B. tyrosine C. lysine D. threonine E. glycine
D
Proteins that bind specific carbohydrates are called ... A. pectins B. oligonucleotides C. glycosaminoglycans D. lectins E. chitins
D
What will happen to a solution of pure α-D-glucopyranose? A. It will remain in solution, as is. B. It will convert completely to the more stable anomer, β-D-glucopyranose. C. It will convert completely to the linear form. D. It will begin converting to the β-anomer, eventually reaching an equilibrium concentration of 63.6 %.
D
Which of the following is not a central role of carbohydrates? A. Energy source. B. Structural material. C. Recognition of cells and Proteins. D. Photoreceptors.
D
Which of the following statements about glycosaminoglycans is strictly true? A. They contain one or more sulfate groups per disaccharide. B. They have repeating units of disaccharides. C. They are made from modified galactose monosaccharides. D. They are highly hydrated, negatively charged linear polymers.
D
Which statement about the ABO blood group antigens is false? A. These antigens occur at the nonreducing ends of the oligosaccharide component of glycolipids. B. These antigens differ because of the activity of a specific glycotransferase. C. Individuals of Type O blood have the H antigen and both anti-A and anti-B antibodies. D. Individuals of Type A blood have both the A antigen and anti-A antibodies.
D
What is the name of the molecule that is formed upon oxidation of the aldehyde to a carboxyl group?
D-gluconic acid, D-g
The ... sugars are monosaccharides in which a hydroxyl group is replaced with a hydrogen.
Deoxy
Glycoproteins A. are only found in bacteria. B. are extremely homogeneous. C. are typically <1% carbohydrate by weight. D. are assembled under strict genetic control. E. are relatively heterogeneous.
E
N-linked oligosaccharides can be covalently linked to proteins at the amino acid A. gly B. ser C. glu D. tyr E. asn
E
The most abundant disaccharide is A. lactose B. cellulose C. α-amylose D. saccharin E. sucrose
E
Uronic acids A. are aldoses where the aldehyde is oxidized. B. are aldoses where the 1° alcohol is oxidized. C. can be found in the pyranose form D. A and C are both correct E. B and C are both correct
E
Which of the following is an example of a heteropolysaccharide? A. cellulose B. chitin C. starch D. glycogen E. glycosaminoglycan
E
Bulky ring substituents preferentially occupy ... positions in the chair conformation.
Equatorial
A lectin is a protein that is capable of binding a wide range of different carbohydrates. True or false?
False
Cellulose is the primary structural component of bacterial cell walls. True or false?
False
L-sugars are epimers of their D-configuration counterparts. True or false?
False
Proteoglycans are complexes formed between proteins and glycogen. True or false?
False
The smallest aldose is ...
Glyceraldehyde
... is the storage polysaccharide in animals.
Glycogen
An example of a homopolysaccharide in liver and muscle is ...
Glycogen
A sugar forms a cyclic-hemiketal by reaction between an alcohol and a ...
Ketone
A ... is a ketone-type carbohydrate of 4 carbon atoms.
Ketotetrose
The disaccharide commonly found in dairy products is ...
Lactose
... is the tendency of glycoproteins to have variable carbohydrate components.
Microheterogenity
Penicillin is an antibiotic that inhibits enzymes that cross-link ... strands.
Peptidoglycan
The main component of a bacterial cell wall is a ...
Peptidoglycan
O-linked oligosaccharides are covalently attached to proteins through the side chain, O atom of ... or threonine.
Serine
Glucose, with its four chiral carbons, has ... possible stereoisomers.
Sixteen
A glycosidic bond connects an anomeric carbon of one sugar to an alcohol oxygen of another sugar. True or false?
True
Almost all secreted proteins are glycosylated. True or false?
True
D-glucose has 4 chiral centers, so it is one of 16 stereoisomers, 8 of which are D-configuration. True or false?
True
Hyaluronic acid is a highly hydrated polymer of D-glucuronic acid and N-acetyl glucosamine that is found in connective tissue, synovial fluid, and the vitreous humor of the eye. True or false?
True
