Deck 20: Carbohydrates

Question 1

A sugar is classified as a d-isomer if the hydroxyl group on the

A)chiral carbon nearest to the carbonyl points to the left.
B)chiral carbon nearest to the carbonyl points to the right.
C)chiral carbon farthest from the carbonyl points to the left.
D)chiral carbon farthest from the carbonyl points to the right.
E)end carbon farthest from the carbonyl points to the left.

Answer 1

chiral carbon farthest from the carbonyl points to the right.

Question 2

Which molecule shown is d-glyceraldehyde?

A)

B)

C)

D)

E)

Answer 2

Question 3

Which molecule shown is a d-isomer?

A)

B)

C)

D)

Answer 3

Question 4

Classify the molecule shown according to the location of its carbonyl group and the number of carbon atoms.

A)aldotriose
B)aldotetrose
C)aldopentose
D)ketotriose
E)ketotetrose

Question 5

How many stereoisomers of an aldotetrose can exist?

A)2
B)4
C)8
D)16
E)32

Question 6

How many chiral carbons are contained in a molecule of ribose?

A)1
B)2
C)3
D)4

Question 7

How many stereoisomers are possible for the following molecule?

A)1
B)2
C)4
D)8
E)16

Question 8

Which of the following is a ketopentose?

A)

B)

C)

D)

E)

Question 9

Molecules such as erythrose and threose,which are stereoisomers but not mirror images,are referred to as a pair of ________.d- and l-threose are mirror images and are referred to as a pair of ________.

A)enantiomers;diastereomers
B)diastereomers;enantiomers
C)anomers;diastereomers
D)diastereomers;anomers
E)anomers;enantiomers

Question 10

Which of the following carbons in the molecule shown is a chiral carbon?

A)carbons 1 and 5
B)carbons 3 and 4
C)carbons 2,3,and 4
D)All carbons are chiral.

Question 11

Ribose can be classified as a(an)

A)aldoketose.
B)aldopentose.
C)aldohexose.
D)ketopentose.
E)ketohexose.

Question 12

Which molecule shown is an l-isomer?

A)

B)

C)

D)

E)

Question 13

Which of the following is an aldopentose?

A)

B)

C)

D)

E)

Question 14

A carbohydrate can be defined as a molecule

A)composed of carbon atoms bonded to water molecules.
B)composed of amine groups and carboxylic acid groups bonded to a carbon skeleton.
C)composed mostly of hydrocarbons and soluble in non-polar solvents.
D)that is an aldehyde or ketone and that has more than one hydroxyl group.
E)whose name ends in "-ase".

Question 15

Left- and right-handed mirror image molecules are known as

A)cis-trans isomers.
B)structural isomers.
C)enantiomers.
D)anomers.
E)diastereomers.

Question 16

Classify the molecule shown according to the location of its carbonyl group and the number of carbon atoms.

A)aldotriose
B)aldotetrose
C)aldopentose
D)ketotriose
E)ketopentose

Question 17

Classify the molecule shown according to the location of its carbonyl group and the number of carbon atoms.

A)aldotriose
B)aldotetrose
C)aldopentose
D)ketotriose
E)ketotetrose

Question 18

How many stereoisomers of an aldopentose can exist?

A)2
B)4
C)8
D)16
E)32

Question 19

Fructose can be classified as a(an)

A)aldoketose.
B)aldopentose.
C)aldohexose.
D)ketopentose.
E)ketohexose.

Question 20

Glucose can be classified as a(an)

A)aldoketose.
B)aldopentose.
C)aldohexose.
D)ketopentose.
E)ketohexose.

Question 21

A hemiacetal linkage consists of a

A)carbon atom bonded to both an -OH and an -OR group.
B)carbonyl group that is also bonded to a hydroxyl group.
C)carbonyl group that is also bonded to an ether linkage.
D)carbon atom bonded to two -OH groups.
E)carbon atom that is bonded to an -OR group and an -NH₂ group.

Question 22

All of the following are common monosaccharides of interest in human biochemistry except

A)glucose.
B)fructose.
C)ribose.
D)galactose.
E)maltose.

Question 23

Mutarotation is process where

A)glucose undergoes reaction to form an equilibrium mixture of anomers.
B)glucose reacts with an alcohol forming a cyclic acetal.
C)the aldehyde group present in a sugar is converted to a hemiacetal.
D)two glucose molecules react to form a disaccharide.
E)glucose isomerizes to fructose.

Question 24

α-d-glucose and β-d-glucose are

A)enantiomers.
B)anomers.
C)disaccharides.
D)a racemic mixture.
E)polysaccharides.

Question 25

The enantiomer of this carbohydrate is

A)

B)

C)

D)

E)none of these

Question 26

A sugar is classified as an l-isomer if the hydroxyl group on the

A)chiral carbon closest to the carbonyl group points to the left.
B)chiral carbon closest to the carbonyl group points to the right.
C)chiral carbon farthest from the carbonyl group points to the left.
D)chiral carbon farthest from the carbonyl group points to the right.
E)end carbon farthest from the carbonyl points to the left.

Question 27

Two isomeric sugars that are cyclic and only differ in the position of the -OH group attached to the hemiacetal carbon are called

A)enantiomers.
B)mutarotations.
C)anomers.
D)epimers.
E)diastereomers.

Question 28

Fructose is similar to glucose and galactose in all of the following aspects except

A)it is a ketose.
B)it forms a hemiacetal ring.
C)it can undergo mutarotation from α to β anomers.
D)its formula is C₆H₁₂O₆.
E)none of the above

Question 29

All of the statements concerning monosaccharides are correct except

A)the number of stereoisomers possible is 2ⁿ,where n is the number of chiral carbon atoms in the molecule.
B)monosaccharides with 5 or 6 carbon atoms exist in solution in cyclic form.
C)the two different cyclic forms of a particular monosaccharide are called tautomers.
D)a molecule is classified as a d or l isomer by the position of the hydroxyl group on the chiral center farthest from the carbonyl group.
E)monosaccharides have the general formula C_n(H₂O)_n,but this only describes the number and kinds of atoms,not their structure.

Question 30

Which of the following is the β-anomer of d-galactose?

A)

B)

C)

D)

E)none of these

Question 31

Draw the Fisher projection for d-galactose using the Haworth structure shown.

Question 32

The conversion of cyclic glucose between the alpha form and the beta form is called

A)dimerization.
B)cyclization.
C)mutarotation.
D)polymerization.
E)hydrolysis.

Question 33

Determine if the following monosaccharides are either a d or an l isomer.Draw the enatiomer.

A)

B)

Question 34

When a monosaccharide forms a cyclic hemiacetal,the carbon atom that contained the carbonyl group is identified as the ________ carbon atom because ________.

A)d;the carbonyl group is drawn to the right
B)l;the carbonyl group is drawn to the left
C)anomeric;its substituents can assume an α or a β position
D)acetal;it forms bonds to an -OR and an -OR'
E)enantiomeric;depending on its position,the resulting ring can have a mirror image

Question 35

A possible diasteromer of this carbohydrate is

A)

B)

C)

D)

E)Both A and D are diasteromers of the carbohydrate shown.

Question 36

Draw the cyclic hemiacetal Haworth structures for α and β anomers of d-talose.

Question 37

Which of the following monosaccharides is present in nucleic acids?

A)glucose
B)galactose
C)ribose
D)fructose

Question 38

Illustrate the conversion between the α and β forms of d-fructose.Make sure to include the open chain form.

Question 39

A glycosidic bond is

A)a bond between any two carbohydrate molecules.
B)a bond formed between an anomeric carbon atom and any -OR group.
C)any bond that can be broken by reaction with water.
D)a bond between anomeric carbon atoms on two separate monosaccharides.
E)none of the above

Question 40

When a monosaccharide forms a ring by interaction of one of its hydroxyl groups with its aldehyde group,the bond is referred to as a(an)________ linkage.

A)ether
B)ester
C)acetal
D)hemiacetal
E)glycosidic

Question 41

The reaction in which a disaccharide is broken down into its component monosaccharides is

A)glycoside formation.
B)hydrolysis.
C)enediol formation.
D)reduction.
E)oxidation.

Question 42

The reaction of a simple sugar with an alcohol produces a

A)glycoside.
B)cyclic acetal.
C)mixture of anomers.
D)all of the above
E)none of the above

Question 43

Which monosaccharide listed is used in the backbone of DNA?

A)glucose
B)ribose
C)deoxyribose
D)mannose
E)fructose

Question 44

Draw the α and β anomers that result from the reaction between glucose and methanol.

Question 45

Ketoses can act as reducing sugars in basic solution because

A)their carbonyl groups can readily be oxidized just as in aldoses.
B)the large number of hydroxyl groups allows oxidation of the molecules.
C)the ketone is converted to an aldehyde by keto-enol tautomerization.
D)mutarotation makes the carbonyl group accessible to oxidizing agents.
E)none of the above

Question 46

Which of the following is the correct structure for glucose 6-phosphate?

A)

B)

C)

D)

E)none of these

Question 47

The molecular formula of the common disaccharides in human biochemistry is

A)CH₂O.
B)C₂(H₂O)₂.
C)C₆H₁₂O₆.
D)C₁₂H₂₂O₁₁.
E)C₁₂H₂₄O₁₂.

Question 48

A sugar present in honey in a 50/50 ratio with glucose is

A)fructose.
B)sucrose.
C)maltose.
D)glucose.
E)mannose.

Question 49

Sucrose is not a reducing sugar because its

A)hemiacetal groups cannot be converted to aldehyde groups.
B)disaccharide bond is an α-1,4 linkage.
C)disaccharide bond is a β-1,4 linkage.
D)disaccharide bond is a 1,2 anomeric link.
E)none of the above

Question 50

________ of glucose leads to gluconic acid.

A)Oxidation
B)Reduction
C)Isomerization
D)Glycosidation
E)Esterification

Question 51

Common reducing reactions of monosaccharides are due to

A)their cyclic structures.
B)the presence of at least one hydroxyl group.
C)the presence of more than one hydroxyl group.
D)the presence of a carbonyl group,usually on the #1 carbon atom.
E)the presence of at least one chiral carbon atom.

Question 52

The bond connecting the two monosaccharides in sucrose is a(an)________ linkage.

A)α-1,4 glycosidic
B)β-1,4 glycosidic
C)1,2 anomeric
D)α-1,6 glycosidic
E)β-1,6 glycosidic

Question 53

The bond connecting the two monosaccharides in maltose is a(an)________ linkage.

A)α-1,4 glycosidic
B)β-1,4 glycosidic
C)1,2 anomeric
D)α-1,6 glycosidic
E)β-1,6 glycosidic

Question 54

Which molecule is a reducing sugar?

A)sucrose
B)maltose
C)starch
D)glycogen
E)amylopectin

Question 55

Glucose and other monosaccharides react with ________ to form phosphate ester in biological systems.

A)ADP
B)AMP
C)phosphoric acid
D)dihydrogen phosphate ion
E)ATP

Question 56

When a cyclic acetal is formed upon the reaction of a monosaccharide and an alcohol the resulting product is called a

A)glycoside.
B)residue.
C)hemiacetal.
D)disacharide.
E)polysacharide.

Question 57

Lactose results from reacting glucose at its ________ carbon and galactose at its ________ carbon.

A)4;1
B)1;4
C)1;6
D)6;1
E)1;1

Question 58

Which of the following molecules has a common name of levulose or fruit sugar?

A)glucose
B)galactose
C)ribose
D)fructose
E)mannose

Question 59

The disaccharide that contains a β-1,4 linkage is

A)sucrose.
B)maltose.
C)amylose.
D)lactose.

Question 60

Which molecule is not a reducing sugar?

A)lactose
B)maltose
C)sucrose
D)glucose
E)galactose

Question 61

Match the following.
enantiomers

A)a monosaccharide that is sweeter than sucrose and found in honey and fruits
B)a monosaccharide that is a component of milk sugar
C)mirror-image forms of chiral molecules
D)a carbohydrate that can be oxidized to produce an acid molecule or its corresponding anion
E)stereoisomers that are not mirror images of each other
F)a disaccharide composed of two molecules of glucose
G)a polysaccharide composed of glucose units joined by β-1,4 linkages
H)a very highly branched polysaccharide composed of glucose units
I)isomers of cyclic sugars that differ in the position of the hydroxyl group at the hemiacetal carbon atom
J)a carbohydrate composed of a large number of monosaccharides chemically combined
K)an aldopentose that is a component of nucleic acids
L)a component of starch composed of glucose units joined by a-1,4 linkages
M)a disaccharide composed of one molecule of glucose and one molecule of fructose
N)a disaccharide composed of one molecule of glucose and one molecule of galactose
O)a monosaccharide that functions as the transport form of carbohydrates in blood
P)a carbohydrate that yields two monosaccharides upon hydrolysis

Question 62

Which of the following statements does not correctly describe functions of modified carbohydrate molecules?

A)Chitins act as a structural component of lobster shells.
B)Heparins form a fibrous network in blood clots.
C)As a component of hemoglobin they transport oxygen.
D)As a receptor molecule on cell surfaces they assist in the functioning of the immune system.
E)As a component of cartilage they provide support to joints.

Question 63

Match the following.
galactose

A)a monosaccharide that is sweeter than sucrose and found in honey and fruits
B)a monosaccharide that is a component of milk sugar
C)mirror-image forms of chiral molecules
D)a carbohydrate that can be oxidized to produce an acid molecule or its corresponding anion
E)stereoisomers that are not mirror images of each other
F)a disaccharide composed of two molecules of glucose
G)a polysaccharide composed of glucose units joined by β-1,4 linkages
H)a very highly branched polysaccharide composed of glucose units
I)isomers of cyclic sugars that differ in the position of the hydroxyl group at the hemiacetal carbon atom
J)a carbohydrate composed of a large number of monosaccharides chemically combined
K)an aldopentose that is a component of nucleic acids
L)a component of starch composed of glucose units joined by a-1,4 linkages
M)a disaccharide composed of one molecule of glucose and one molecule of fructose
N)a disaccharide composed of one molecule of glucose and one molecule of galactose
O)a monosaccharide that functions as the transport form of carbohydrates in blood
P)a carbohydrate that yields two monosaccharides upon hydrolysis

Question 64

Glycogen is produced by ________,and its major function is ________.

A)animals;energy storage
B)animals;as a structural component
C)plants;as a structural component
D)plants;energy storage
E)none of the above

Question 65

Describe the similarities and differences in the structures of the two polysaccharides that comprise starch.Make sure you state their names and what type of linkage holds the monomer units together.

Question 66

Glycoproteins are formed by bonding an oligosaccharide to a protein through a ________ linkage.

A)glycosidic
B)glucuronic
C)imine
D)ester
E)ether

Question 67

Which of the following polysaccharides is used to inhibit blood clotting?

A)chitin
B)heparin
C)amylopectin
D)hyaluronic acid

Question 68

Match the following.
diastereomers

A)a monosaccharide that is sweeter than sucrose and found in honey and fruits
B)a monosaccharide that is a component of milk sugar
C)mirror-image forms of chiral molecules
D)a carbohydrate that can be oxidized to produce an acid molecule or its corresponding anion
E)stereoisomers that are not mirror images of each other
F)a disaccharide composed of two molecules of glucose
G)a polysaccharide composed of glucose units joined by β-1,4 linkages
H)a very highly branched polysaccharide composed of glucose units
I)isomers of cyclic sugars that differ in the position of the hydroxyl group at the hemiacetal carbon atom
J)a carbohydrate composed of a large number of monosaccharides chemically combined
K)an aldopentose that is a component of nucleic acids
L)a component of starch composed of glucose units joined by a-1,4 linkages
M)a disaccharide composed of one molecule of glucose and one molecule of fructose
N)a disaccharide composed of one molecule of glucose and one molecule of galactose
O)a monosaccharide that functions as the transport form of carbohydrates in blood
P)a carbohydrate that yields two monosaccharides upon hydrolysis

Question 69

Explain why cows and other grazing animals can eat grass and benefit from its nutritive value,but humans cannot.

Question 70

Which of the following statements comparing amylopectin and glycogen is false?

A)Both serve as energy storage molecules.
B)Both are polymers of α-d-glucose.
C)Glycogen molecules are generally larger than amylopectin molecules.
D)Glycogen is more highly branched than amylopectin.
E)none of the above

Question 71

The following compound can be described as a(an)

A)uronic acid.
B)aldonic acid.
C)sugar phosphate.
D)amino sugar derivative.
E)disaccharide.

Question 72

Match the following.
anomers

A)a monosaccharide that is sweeter than sucrose and found in honey and fruits
B)a monosaccharide that is a component of milk sugar
C)mirror-image forms of chiral molecules
D)a carbohydrate that can be oxidized to produce an acid molecule or its corresponding anion
E)stereoisomers that are not mirror images of each other
F)a disaccharide composed of two molecules of glucose
G)a polysaccharide composed of glucose units joined by β-1,4 linkages
H)a very highly branched polysaccharide composed of glucose units
I)isomers of cyclic sugars that differ in the position of the hydroxyl group at the hemiacetal carbon atom
J)a carbohydrate composed of a large number of monosaccharides chemically combined
K)an aldopentose that is a component of nucleic acids
L)a component of starch composed of glucose units joined by a-1,4 linkages
M)a disaccharide composed of one molecule of glucose and one molecule of fructose
N)a disaccharide composed of one molecule of glucose and one molecule of galactose
O)a monosaccharide that functions as the transport form of carbohydrates in blood
P)a carbohydrate that yields two monosaccharides upon hydrolysis

Question 73

A)What is the name of the following disaccharide?
B) What two monosaccharides compose it?
C) What type of glycosidic linkage is between the two?

Question 74

Starch is composed of two polymers,________,which is an unbranched chain,and ________,which is a branched polymer.

A)amylose;amylase
B)amylase;amylose
C)amylopectin;amylose
D)amylose;amylopectin
E)amylase;amylopectin

Question 75

Cellulose is produced by ________,and its major function is ________.

A)animals;energy storage
B)animals;as a structural component
C)plants;as a structural component
D)plants;energy storage
E)none of the above

Question 76

Which polysaccharide has only β-1,4 glycosidic linkages?

A)cellulose
B)glycogen
C)amylose
D)amylopectin
E)starch

Question 77

Match the following.
fructose

A)a monosaccharide that is sweeter than sucrose and found in honey and fruits
B)a monosaccharide that is a component of milk sugar
C)mirror-image forms of chiral molecules
D)a carbohydrate that can be oxidized to produce an acid molecule or its corresponding anion
E)stereoisomers that are not mirror images of each other
F)a disaccharide composed of two molecules of glucose
G)a polysaccharide composed of glucose units joined by β-1,4 linkages
H)a very highly branched polysaccharide composed of glucose units
I)isomers of cyclic sugars that differ in the position of the hydroxyl group at the hemiacetal carbon atom
J)a carbohydrate composed of a large number of monosaccharides chemically combined
K)an aldopentose that is a component of nucleic acids
L)a component of starch composed of glucose units joined by a-1,4 linkages
M)a disaccharide composed of one molecule of glucose and one molecule of fructose
N)a disaccharide composed of one molecule of glucose and one molecule of galactose
O)a monosaccharide that functions as the transport form of carbohydrates in blood
P)a carbohydrate that yields two monosaccharides upon hydrolysis

Question 78

Match the following.
ribose

A)a monosaccharide that is sweeter than sucrose and found in honey and fruits
B)a monosaccharide that is a component of milk sugar
C)mirror-image forms of chiral molecules
D)a carbohydrate that can be oxidized to produce an acid molecule or its corresponding anion
E)stereoisomers that are not mirror images of each other
F)a disaccharide composed of two molecules of glucose
G)a polysaccharide composed of glucose units joined by β-1,4 linkages
H)a very highly branched polysaccharide composed of glucose units
I)isomers of cyclic sugars that differ in the position of the hydroxyl group at the hemiacetal carbon atom
J)a carbohydrate composed of a large number of monosaccharides chemically combined
K)an aldopentose that is a component of nucleic acids
L)a component of starch composed of glucose units joined by a-1,4 linkages
M)a disaccharide composed of one molecule of glucose and one molecule of fructose
N)a disaccharide composed of one molecule of glucose and one molecule of galactose
O)a monosaccharide that functions as the transport form of carbohydrates in blood
P)a carbohydrate that yields two monosaccharides upon hydrolysis

Question 79

Match the following.
glucose

A)a monosaccharide that is sweeter than sucrose and found in honey and fruits
B)a monosaccharide that is a component of milk sugar
C)mirror-image forms of chiral molecules
D)a carbohydrate that can be oxidized to produce an acid molecule or its corresponding anion
E)stereoisomers that are not mirror images of each other
F)a disaccharide composed of two molecules of glucose
G)a polysaccharide composed of glucose units joined by β-1,4 linkages
H)a very highly branched polysaccharide composed of glucose units
I)isomers of cyclic sugars that differ in the position of the hydroxyl group at the hemiacetal carbon atom
J)a carbohydrate composed of a large number of monosaccharides chemically combined
K)an aldopentose that is a component of nucleic acids
L)a component of starch composed of glucose units joined by a-1,4 linkages
M)a disaccharide composed of one molecule of glucose and one molecule of fructose
N)a disaccharide composed of one molecule of glucose and one molecule of galactose
O)a monosaccharide that functions as the transport form of carbohydrates in blood
P)a carbohydrate that yields two monosaccharides upon hydrolysis

Question 80

Starch is produced by ________,and its major function is ________.

A)animals;energy storage
B)animals;as a structural component
C)plants;as a structural component
D)plants;energy storage
E)none of the above