Carbohydrates

Question 1

Which of the following monosaccharides is a ketose?
a. glucose
b. fructose
c. galactose
d. mannose

Answer 1

b

Question 2

Which of the following monosaccharides is an aldose
a. glucose
b. galactose
c. mannose
d. ribose
e. all of them

Answer 2

e

Question 3

Which of the following monosaccharides is a ketose?
a. arabinose
b. ribose
c. xylose
d. lyxose
e. none of them

Answer 3

e

Question 4

Haworth projection formulas
a. are representations of the cyclic form of sugars
b. can show the distinction between the α and β anomers
c. both of the above
d. neither of the above

Answer 4

c

Question 5

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.

Answer 5

d

Question 6

How many carbon atoms are in the simplest carbohydrates?
a. 1
b. 2
c. 3
d. 4
e. 5

Answer 6

c

Question 7

The simplest ketotriose is
a. glyceraldehyde.
b. dihydroxyacetone.
c. ribose.
d. glucose.
e. sucrose.

Answer 7

b

Question 8

Mirror image stereoisomers are called
a. anomers.
b. diastereoisomers.
c. enantiomers.
d. epimers.

Answer 8

c

Question 9

The simplest aldotriose is:
a. acetone
b. dihydroxyacetone
c. glyceraldehyde
d. threose

Answer 9

c

Question 10

In a Fischer projection, which chiral carbon determines whether the sugar is the D- or the L-isomer?
a. highest numbered carbon atom
b. lowest numbered asymmetric carbon atom
c. lowest numbered carbon atom
d. highest numbered asymmetric carbon atom

Answer 10

d

Question 11

….OH
|
H-C-H
|
C=O
|
H-C-OH
|
HO-C-H
|
H-C-OH
|
H-C-H
|
OH
The carbohydrate shown is
a. a monosaccharide
b. a ketose.
c. a hexose.
d. all of these
e. none of these

Answer 11

d

Question 12

….OH
|
H-C-H
|
C=O
|
H-C-OH
|
HO-C-H
|
H-C-OH
|
H-C-H
|
OH
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.

Answer 12

a

Question 13

For the α 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.

Answer 13

b

Question 14

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.

Answer 14

b

Question 15

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 α and β forms of cyclic sugars.
d. two related compounds, pyran and furan

Answer 15

b

Question 16

D-erythrose is to D-ribose
as D-ribose is to:
a. D-allose
b. D-altrose
c. D-glucose
d. D-galactose

Answer 16

a

Question 17

How many enantiomeric pairs are possible for a aldohexose?
a. 2
b. 4
c. 8
d. 16

Answer 17

c

Question 18

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

Answer 18

d

Question 19

Aldoses can form which type of cyclic structure?
a. Hemiacetal
b. Hemiketal
c. Both hemiacetal and hemiketal
d. Neither hemiacetal and hemiketal

Answer 19

a

Question 20

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.

Answer 20

a

Question 21

The enantiomer of D-glucose is:
a. D-Fructose
b. D-Glucose
c. L-Glucose
d. L-Idose
e. D-Galactose

Answer 21

c

Question 22

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

Answer 22

d

Question 23

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.

Answer 23

a

Question 24

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

Answer 24

e

Question 25

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.

Answer 25

a

Question 26

The α and β forms of the same sugar are called a. anomers. b. diastereoisomers. c. enantiomers. d. epimers. e. none of these

Answer 26

a

Question 27

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.

Answer 27

b

Question 28

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.

Answer 28

a

Question 29

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.

Answer 29

b

Question 30

Which of the following groups is produced when an aldehyde is oxidized? a. ketone b. carboxyl c. alcohol d. ether

Answer 30

b

Question 31

A lactone is a cyclic a. ether. b. ester. c. ketone. d. alcohol.

Answer 31

b

Question 32

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

Answer 32

c

Question 33

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.

Answer 33

a

Question 34

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.

Answer 34

a

Question 35

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

Answer 35

e

Question 36

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

Answer 36

d

Question 37

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 d. none of these

Answer 37

c

Question 38

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.

Answer 38

b

Question 39

Glycosidic linkages between monosaccharide units may vary based on a. the anomeric form of the cyclic structure, i.e., α or β. b. which −OH group is involved. c. both of these d. none of these

Answer 39

c

Question 40

Common table sugar is a. glucose b. fructose c. sucrose d. maltose e. lactose

Answer 40

c

Question 41

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

Answer 41

e

Question 42

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

Answer 42

b

Question 43

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

Answer 43

d

Question 44

Which of the following is not a reducing sugar? a. glucose b. fructose c. sucrose d. maltose e. lactose

Answer 44

c

Question 45

Which of the following artificial sweeteners is a chemical derivative of sucrose? a. saccharin b. cyclamates c. sucralose d. aspartame

Answer 45

c

Question 46

Which of the following is true about Sucralose a. it is an artificial sweetener b. It is exactly like sucrose except for the presence of 3 chlorine atoms c. It is a dissacharide made up of glucose and fructose d. all of these

Answer 46

a

Question 47

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

Answer 47

d

Question 48

The following sugar is also called milk sugar: a. Fructose b. Glucose c. Lactose d. Sucrose e. Maltose

Answer 48

c

Question 49

The following sugar is also called fruit sugar: a. Fructose b. Glucose c. Lactose d. Sucrose e. Maltose

Answer 49

a

Question 50

The following sugar is also called blood sugar: a. Fructose b. Glucose c. Lactose d. Sucrose e. Maltose

Answer 50

b

Question 51

Which of the following molecules is a disaccharide? a. glucose b. lactose c. fructose d. galactose

Answer 51

b

Question 52

Which of the following is a disaccharide? a. sucrose b. lactose c. maltose d. cellobiose e. all of them

Answer 52

e

Question 53

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

Answer 53

a

Question 54

Which of the following disaccharides cannot be digested by mammals? a. cellobiose b. sucrose c. maltose d. lactose

Answer 54

a

Question 55

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

Answer 55

d

Question 56

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 α-glycosidic linkages between the monomer units c. animals do not have the enzymes needed to hydrolyze the β-glycosidic linkages between the monomer units d. its molecular weight is too high for it to be degraded by enzymes

Answer 56

c

Question 57

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 β linkage in the cellulose. d. Cellulose is insoluble and we lack the enzyme to break the β linkage in the cellulose. e. All of these are reasons why we cannot digest cellulose.

Answer 57

d

Question 58

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

Answer 58

c

Question 59

Which of the following molecules have the highest degree of α[1−6] branching linkages a. Amylose b. Amylopectin c. Starch d. Glycogen e. All of these have the same degree of branching

Answer 59

d

Question 60

A major difference between amylose and amylopectin is that a. amylose is connected by α(1−4) bonds and amylopectin is connected by β(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.

Answer 60

c

Question 61

The linkage between the glucose residues in amylopectin and glycogen is: a. For the main chain α (1 → 4) and β (1 → 4) for the branches b. For the main chain α (1 → 6) and α (1 → 4) for the branches c. For the main chain α (1 → 4) and α (1 → 6) for the branches d. For the main chain β (1 → 4) and β (1 → 6) for the branches e. The linkage between the glucose residues is variable.

Answer 61

c

Question 62

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

Answer 62

c

Question 63

Which of the following has only α[1−4] linkages and no α[1−6] linkages a. Glycogen b. Amylose c. Amylopectin d. Starch e. Cellobiose

Answer 63

b

Question 64

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

Answer 64

b

Question 65

Glycogen breakdown proceeds from the nonreducing ends. a. True b. False

Answer 65

a

Question 66

Glycogen is sometimes called animal starch a. True b. False

Answer 66

a

Question 67

Plant starch includes amylopectin and cellulose a. True b. False

Answer 67

b

Question 68

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.

Answer 68

b

Question 69

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

Answer 69

d

Question 70

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

Answer 70

c

Question 71

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.

Answer 71

e

Question 72

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

Answer 72

b

Question 73

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

Answer 73

a

Question 74

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

Answer 74

b

Question 75

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.

Answer 75

b

Question 76

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

Answer 76

a

Question 77

Polysaccharides used in cell wall structure contribute rigidity to the wall due to covalent cross-linking between the fibers. a. True b. False

Answer 77

b

Question 78

Chitin, which forms the exoskeletons of insects, is composed of a. α(1−4) linked N-acetylglucosamine residues b. β(1−4) linked N-acetylglucosamine residues c. α(1−4) linked glucose residues d. β(1−4) linked glucose residues

Answer 78

b

Question 79

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

Answer 79

a

Question 80

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.

Answer 80

d

Question 81

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

Answer 81

a

Question 82

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

Answer 82

d

Question 83

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

Answer 83

b

Question 84

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

Answer 84

b

Question 85

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

Answer 85

a

Question 86

Which of the following types of carbohydrates are made up of sugars linked by glycosidic bonds? a. Monosaccharides b. Aldoses c. Oligosaccharides d. Ketoses

Answer 86

c

Question 87

Explain how a hemiacetal compound differs from a hemiketal compound.

Answer 87

A hemiacetal compound is formed by the reaction of an aldehyde with an alcohol and is found in the cyclic structure of sugars, whereas a hemiketal compound is formed by the reaction of a ketone with an alcohol and is found in the cyclic structure of sugars.

Question 88

Which of the following reagents is used to detect the presence of reducing sugars? a. Fehling’s reagent b. Millon’s reagent c. Cornforth reagent d. Tollens’ reagent

Answer 88

d

Question 89

Explain how starch and cellulose differ from one another.

Answer 89

Starch is a polymer of α-D-glucose that occurs in plant cells, usually as starch granules in the cytosol. On the other hand, cellulose is a linear homopolysaccharide of β-D-glucose, and all residues are linked in β(1 → 4) glycosidic bonds. Cellulose is the major structural component of plants.

Question 90

Peptidoglycan can be described as a polysaccharide that contains _____. a. D-galacturonic acid b. coniferyl alcohol c. glycosidic links d. peptide crosslinks

Answer 90

d