Unit 4 Carbohydrates

. Blood typing depends on A. the nature of the oligosaccharide portion of glycoproteins on the surface of red blood cells B. the presence of a polysaccharide coating on red blood cells C. the presence of a polysaccharide coating on white blood cells D. the addition of sucrose to blood before storage

A

A furanose is a sugar that A. contains a five-membered ring as part of its cyclic structure. B. contains a six-membered ring as part of its cyclic structure. C. is a five-carbon open-chain sugar. D. is a six-carbon open-chain sugar

A

Aldoses can form which type of cyclic structure? A. Hemiacetal B. Hemiketal C. Both hemiacetal and hemiketal D. Neither hemiacetal and hemiketal

A

Blood typing depends on A. the nature of the oligosaccharide portion of glycoproteins on the surface of red blood cells B. the presence of a polysaccharide coating on red blood cells C. the presence of a polysaccharide coating on white blood cells D. the addition of sucrose to blood before storage

A

Glycogen breakdown proceeds from the nonreducing ends. A. True B. False

A

Glycogen is sometimes called animal starch A. True B. False

A

Insoluble fiber in the diet is better at better at providing bulk and stimulating peristaltic action than soluble fiber. A. True B. False

A

Lactose intolerance A. arises from inability to metabolize the disaccharide lactose B. depends on a deficiency of sucrose in the diet C. is based on the composition of lactose, consisting glucose and fructose in glycosidic linkage D. arises because lactose is a dimer of galactose

A

One advantage of branched sugar polymers is the availability of more ends for chemical reaction. A. True B. False

A

One major difference between bacterial and plant cell walls is that bacterial cell walls have polysaccharides that are crosslinked by peptides. A. True B. False

A

Refer to Exhibit 16A. Diastereoisomers of D-Glucose include all of these, except: A. D-Fructose B. L-Glucose C. L-Idose D. D-Galactose E. All of these are diastereoisomers of D-Glucose

A

Refer to Exhibit 16B. The carbohydrate shown is A. the D isomer. B. the L isomer. C. both D and L. D. neither D nor L. E. It's impossible to tell from a picture which isomer this is

A

See figure 16.4 in the textbook. D-erythrose is to D-ribose as D-ribose is to: A. D-allose B. D-altrose C. D-glucose D. D-galactose

A

The a and b forms of the same sugar are called A. anomers. B. diastereoisomers. C. enantiomers. D. epimers. E. none of these

A

The conversion of a sugar's carbonyl to an alcohol is A. a reduction reaction. B. an oxidation reaction. C. a glycosidic reaction. D. impossible.

A

The cyclic form of sugars A. has one more chiral center (the anomeric carbon) than the open-chain form. B. loses a chiral center compared to the open-chain form. C. is not usually found in nature. D. has one more carbon atom than the open-chain form. E. has one less carbon atom than the open-chain form.

A

The following sugar is also called fruit sugar: A. Fructose B. Glucose C. Lactose D. Sucrose E. Maltose

A

Two samples containing identical mixtures of sugars are analyzed, one using Tollen's reagent, the other with glucose oxidase. Which will give a stronger reaction? A. Tollen's reagent B. glucose oxidase C. They will have identical strengths. D. It's impossible to predict from the information provided.

A

Which carbon of the open-chain form of a sugar becomes the anomeric carbon in the cyclic form? A. the carbonyl carbon B. the highest numbered chiral center C. the highest numbered carbon D. It depends on the individual sugar

A

Which of the following disaccharides cannot be digested by mammals? A. cellobiose B. sucrose C. maltose D. lactose

A

Which of the following is true about the ABO blood groups? A. all three of the blood groups have an á-L-fucose group attached B. type O blood is the universal donor because it has an á-L-fucose group C. type A blood has a â-N-acetylgalactosamine group D. type AB blood is the universal donoR

A

Cartilage and mucous are both slippery because: A. Short polymers comprise these compounds. B. The charge repulsion between the many acid groups in these polymers. C. The sticky nature of sugars. D. Both charge repulsion of acidic groups and the sticky nature of sugars. E. All of these

D

Deoxyribose is best described as a(n): A. oxidized form of ribose B. reduced pyranose C. polyhydroxyl alcohol D. glycoside E. reduced form of a pentose

D

Humans are not able to digest cellulose as a food source because: A. Cellulose is very insoluble. B. It is more important that the cellulose is used as fiber in our bodies. C. We lack the enzyme to break the b linkage in the cellulose. D. Cellulose is insoluble and we lack the enzyme to break the b linkage in the cellulose. E. All of these are reasons why we cannot digest cellulose

D

In a Fischer projection, which chiral carbon determines whether the sugar is the D- or the Lisomer? A. highest numbered carbon atom B. lowest numbered asymmetric carbon atom C. lowest numbered carbon atom D. highest numbered asymmetric carbon atom

D

Refer to Exhibit 16A. Epimers of D-Glucose include: A. D-Fructose and L-Glucose B. D-Glucose and L-Glucose C. L-Glucose and L-Idose D. L-Idose and D-Galactose E. L-Glucose and D-Galactose

D

Refer to Exhibit 16B. The carbohydrate shown is A. a monosaccharide B. a ketose. C. a hexose. D. all of these E. none of these

D

Refer to Exhibit 16C. Which lettered subunit is the nonreducing end? A. A B. B C. C D. There is more than one nonreducing end on this carbohydrate. E. There are no nonreducing ends on this carbohydrate.

D

Sugars which differ in chirality only around one carbon are most specifically called A. anomers. B. diastereoisomers. C. enantiomers. D. epimers. E. none of these

D

The difference between cellobiose and maltose is: A. one contains glucose and the other fructose B. they contain different monosaccharides C. they both contain glucose units but are connected together at different carbons D. one has an á linkage and the other a â linkage E. there is no difference between the two

D

There are two forms of starch: A. amylose and glycogen, both of which are highly branched polysaccharides B. glycogen and chitin, both of which are linear polysaccharides C. amylopectin and glycogen, both of which are linear polysaccharides D. amylose, which is a linear polysaccharide, and amylopectin, which is highly branched

D

When monosaccharides are bonded together A. one H2O molecule is lost for each new link formed. B. oligosaccharides are formed by combining a few monosaccharides. C. polysaccharides are formed by combining many monosaccharides. D. all of these

D

Which of the following is not a function of carbohydrates? A. They are major energy sources. B. They play key roles in processes that take place on the surface of cells. C. They are used in structural roles. D. They are catalytic components of enzymes.

D

Which of the following is true concerning the molecule pictured? A. It would give a positive reaction in a Tollen's silver mirror test B. It is a reducing sugar C. It is not a reducing sugar because it is an aldose D. It is not a reducing sugar because the anomeric hydroxyl is methlyated

D

Which of the following molecules have the highest degree of a[1-6] branching linkages A. Amylose B. Amylopectin C. Starch D. Glycogen E. All of these have the same degree of branching

D

A bacterial cell wall is composed of: A. A polysaccharide consisting of a single type of monosaccharide unit and cross-linking oligopeptides. B. A polysaccharide consisting of 2 types of monosaccharide units and cross-linking oligopeptides. C. A polysaccharide consisting of 3 types of monosaccharide units and cross-linking oligopeptides. D. Two different polysaccharides and 1 type of oligopeptide, which are cross-linked.

B

A lactone is a cyclic A. ether. B. ester. C. ketone. D. alcohol.

B

A pyranose is a sugar that A. contains a five-membered ring as part of its cyclic structure. B. contains a six-membered ring as part of its cyclic structure. C. is a five-carbon open-chain sugar. D. is a six-carbon open-chain sugar

B

Cell walls A. occur in plants, animals, and bacteria B. are found in plants and bacteria, but have different chemical compositions C. have the same chemical composition in plants and bacteria D. have the same chemical composition in plants and animals

B

Chitin, which forms the exoskeletons of insects, is composed of A. a(1-4) linked N-acetylglucosamine residues B. b(1-4) linked N-acetylglucosamine residues C. a(1-4) linked glucose residues D. b(1-4) linked glucose residues

B

Diastereomers are A. mirror-image, nonsuperimposable stereoisomers. B. non-mirror-image, nonsuperimposable stereoisomers. C. stereoisomers with one or more double bonds. D. none of the above

B

Epimers are A. stereoisomers that differ from each other in their configuration at two or more carbon atoms. B. stereoisomers that differ from each other in their configuration at a single carbon atom. C. the a and b forms of cyclic sugars. D. two related compounds, pyran and furan.

B

For a D-sugar, any group that is written to the right of the carbon in a Fischer projection A. has an upward projection in a Haworth projection. B. has a downward projection in a Haworth projection. C. may be either up or down in a Haworth projection, it depends on the individual sugar. D. is missing from a Haworth projection.

B

For the a anomer of a D-sugar, the anomeric hydroxyl in a Haworth projection A. has an upward projection (on the same side as the terminal CH2OH group). B. has a downward projection (on the opposite side from the terminal CH2OH group). C. may be either up or down, it depends on the individual sugar. D. is non-existent; anomers are a consideration only in Fischer projections

B

Glycogen has a similar structure to amylopectin, but is less highly branched. A. True B. False

B

Glycoproteins A. are involved in the metabolism of sugars B. are proteins to which sugars are covalently bonded C. occur in the bloodstream of diabetics D. have not been found in nature, but have been synthesized in the laboratory

B

Insoluble fiber in the diet is better at binding toxic substances than soluble fiber. A. True B. False

B

Lactose is composed of the following simple sugars: A. galactose only B. glucose only C. fructose only D. galactose and glucose E. glucose and fructose F. galactose and fructose

B

Maltose is composed of the following simple sugars: A. galactose only B. glucose only C. fructose only D. galactose and glucose E. glucose and fructose F. galactose and fructose

B

Plant starch includes amylopectin and cellulose A. True B. False

B

Polysaccharides used in cell wall structure contribute rigidity to the wall due to covalent crosslinking between the fibers. A. True B. Fals

B

Refer to Exhibit 16C. Which best describes the polysaccharide? A. homopolysaccharide B. heteropolysaccharide C. aminopolysaccharide D. cryptopolysaccharide

B

The following sugar is also called blood sugar: A. Fructose B. Glucose C. Lactose D. Sucrose E. Maltose

B

The main difference, on the surface of a red blood cell, between the A-B-O major blood groups depends on A. the presence or absence of a certain protein sequence. B. the presence or absence of a certain sugar. C. the presence or absence of an acetyl group on a sugar. D. all of these

B

The most common biopolymer on earth is this carbohydrate: A. Glucose B. Cellulose C. Starch D. Chitin E. None of these carbohydrates is very common

B

The simplest ketotriose is A. glyceraldehyde. B. dihydroxyacetone. C. ribose. D. glucose. E. sucrose.

B

Which of the following groups is produced when an aldehyde is oxidized? A. ketone B. carboxyl C. alcohol D. ether

B

Which of the following has only a[1-4] linkages and no a[1-6] linkages A. Glycogen B. Amylose C. Amylopectin D. Starch E. Cellobiose

B

Which of the following molecules is a disaccharide? A. glucose B. lactose C. fructose D. galactose

B

Which of the following monosaccharides is a ketose? A. glucose B. fructose C. galactose D. mannose

B

Which of the following statements concerning sugar polymers is false? A. Branched polymers have one non-reducing end and many reducing ends. B. Linear polymers are more water-soluble than branched ones. C. Branched polymers are more water-soluble than linear ones. D. Sugar polymers may vary both in the composition of the sugar monomers and in the types of connecting glycosidic bonds.

B

A major difference between amylose and amylopectin is that A. amylose is connected by a(1-4) bonds and amylopectin is connected by b(1-4) bonds. B. amylose is branched and amylopectin is not. C. amylopectin is branched and amylose is not. D. each is composed different types of sugar residues.

C

Cellulose is indigestible to most animals because A. animals do not have the enzymes needed to hydrolyze ester linkages between the monomer units B. animals do not have the enzymes needed to hydrolyze the a-glycosidic linkages between the monomer units C. animals do not have the enzymes needed to hydrolyze the b-glycosidic linkages between the monomer units D. its molecular weight is too high for it to be degraded by enzymes

C

Common table sugar is A. glucose B. fructose C. sucrose D. maltose E. lactose

C

Glycogen is A. polysaccharide storage polymer found in plants B. a linear polysaccharide C. a highly branched polysaccharide found in animals D. a synthetic sugar substitute

C

Glycosidic bonds from sugars A. always link to the other molecule through an oxygen atom. B. always link to the other molecule through a nitrogen atom. C. may link to the other molecule through either an oxygen or a nitrogen atom

C

Glycosidic linkages between monosaccharide units may vary based on A. the anomeric form of the cyclic structure, i.e., a or b. B. which -OH group is involved. C. both of these D. none of these

C

Haworth projection formulas A. are representations of the cyclic form of sugars B. can show the distinction between the a and b anomers C. both of the above D. neither of the above

C

How many carbon atoms are in the simplest carbohydrates? A. 1 B. 2 C. 3 D. 4 E. 5

C

How many enantiomeric pairs are possible for a aldohexose? A. 2 B. 4 C. 8 D. 16

C

In bacterial cell walls A. polysaccharides form nonspecific mixtures with proteins B. polysaccharides are hydrogen bonded together C. peptides form crosslinks between polysaccharides D. oligosaccharides form crosslinks between proteins

C

Mirror image stereoisomers are called A. anomers. B. diastereoisomers. C. enantiomers. D. epimers

C

Refer to Exhibit 16A. The enantiomer of D-glucose is: A. D-Fructose B. D-Glucose C. L-Glucose D. L-Idose E. D-Galactose

C

Refer to Exhibit 16C. Which best describes bond #3? A. a[1,3] B. b[1,3] C. a[2,4] D. b[2,4] E. None of the above is a proper description.

C

Refer to Exhibit 16C. Which lettered subunit is the reducing end? A. A B. B C. C D. There is more than one nonreducing end on this carbohydrate. E. There are no nonreducing ends on this carbohydrate.

C

The blue color in a well-known test for the presence of starches is due to A. the formation of crosslinks between molecules of starch, caused by the addition of Cu2+ B. the reaction of the silver-ammonia complex ion with the hydroxyl groups of the starch C. the formation of a complex between iodine and amylose D. none of these

C

The following sugar is also called milk sugar: A. Fructose B. Glucose C. Lactose D. Sucrose E. Maltose

C

The linkage between the glucose residues in amylopectin and glycogen is: A. For the main chain a (1 ® 4) and b (1 ® 4) for the branches B. For the main chain a (1 ® 6) and a (1 ® 4) for the branches C. For the main chain a (1 ® 4) and a (1 ® 6) for the branches D. For the main chain b (1 ® 4) and b (1 ® 6) for the branches E. The linkage between the glucose residues is variable

C

The simplest aldotriose is: A. acetone B. dihydroxyacetone C. glyceraldehyde D. threose

C

Which of the following artificial sweeteners is a chemical derivative of sucrose? A. saccharin B. cyclamates C. sucralose D. aspartame

C

Which of the following best describes the glycosidic bond in the disaccharide shown? A. a(1-4) B. b(1-4) C. a(2-4) D. b(2-4) E. None of the above

C

Which of the following compounds is produced by oxidation of an aldose in the cyclic form? A. a hemiacetal B. a hemiketal C. a lactone D. an amino sugar

C

Which of the following is not a reducing sugar? A. glucose B. fructose C. sucrose D. maltose E. lactose

C

Which of the following statements associated with cellulose is false? A. It's a linear polymer of glucose. B. The glycosidic linkage is b(1 ® 4). C. Hydrolysis is accomplished enzymatically by cellulase. D. Most animals can easily digest this compound

D

Which of the following statements concerning plant cell walls is false? A. They are composed of a polysaccharide and protein matrix. B. They contain a lipid bilayer. C. They are porous to small molecules. D. They contain large amounts of protein

D

Amino or acid derivatives of sugars are very important in which of the following biological functions? A. Structural roles B. Lubricating fluids C. Cell surface sugars used in cell identity D. Both structural roles and lubricating fluids. E. All of the above are functions of amino and acid sugar derivatives.

E

Isomers of sugars in which the position of ketone and aldehyde groups have been changed are called A. anomers. B. diastereoisomers. C. enantiomers. D. epimers. E. none of these

E

Sucrose is composed of the following simple sugars: A. galactose only B. glucose only C. fructose only D. galactose and glucose E. glucose and fructose F. galactose and fructose

E