Deck 8: Carbohydrates

Question 1

Which is true about naturally occurring monosaccharides?

A)The L-isomers predominate.
B)The D-isomers predominate.
C)The L and D-isomers occur in equal ratios.
D)The ratio of L and D-isomers varies widely depending on the source.

Answer 1

The D-isomers predominate.

Question 2

Which does not apply to dihydroxyacetone?

A)Ketose.
B)Triose.
C)Chiral.
D)Water-soluble.

Answer 2

Chiral.

Question 3

A saccharide is a ________.

A)lipid
B)carbohydrate
C)nucleic acid
D)protein

Answer 3

carbohydrate

Question 4

Which is not a glycoconjugate?

A)Proteoglycan.
B)Glycolipid.
C)Glycoprotein.
D)Homoglycan.

Question 5

The functional group shown is a(n)________.

A)hemiacetal
B)hemiketal
C)acetal
D)ketal

Question 6

Which structure is NOT a carbohydrate?

A)
B)
C)
D)

Question 7

The structure of D-arabinose is shown below.How many stereoisomers are possible for this molecule (including the one shown)?

A)One
B)Four
C)Six
D)Eight

Question 8

Examine the cyclic D-monosaccharide shown below.The ring structure is the ________ and the linear form of this monosaccharide must be a(n)________.

A)α anomer;ketose
B)β anomer;ketose
C)α anomer;aldose
D)β anomer;aldose

Question 9

Which is a general term indicating a carbohydrate polymer?

A)Glycan.
B)Polycarb.
C)Multimer.
D)Oligosaccharide.

Question 10

Anomers can be interconverted ________.

A)by rotation about carbon-carbon bonds
B)via a linear intermediate
C)by an isotopic exchange reaction
D)None of the above.Anomers cannot be interconverted.

Question 11

The intramolecular cyclization reaction of glucose in solution ________.

A)generates a chiral center
B)yields a hemiacetal
C)usually forms a pyranose
D)All of the above

Question 12

Below is the structure for a cyclic D-monosaccharide.Which is the anomeric carbon atom?

A)1
B)2
C)3
D)4
E)5

Question 13

In solution α-D-glucopyranose and β-D-glucopyranose ________.

A)rapidly polymerize to form a heteropolymer
B)can never exist together
C)form a racemic mixture
D)form an equilibrium mixture

Question 14

The Fischer projections of linear D-glucose and D-galactose are shown below.These two molecules are ________.

A)epimers
B)enantiomers
C)anomers
D)structural (constitutional)isomers

Question 15

Which is a product of the intramolecular cyclization of D-tagatose to form a furanose?

A)I
B)II
C)III
D)IV

Question 16

The compounds α-D-fructofuranose and β-D-fructofuranose are ________.

A)enantiomers
B)mutamers
C)anomers
D)conformational isomers

Question 17

The structures of D-ribose and D-arabinose are shown below.These two molecules are ________.

A)epimers
B)enantiomers
C)tautomers
D)anomers

Question 18

Below is the Fischer projection of D-galactose.Which is the proper Haworth projection of β-D-galactopyranose?

A)I
B)II
C)III
D)IV

Question 19

Examine the Fischer projection below.How is this carbohydrate classified?

A)L enantiomer;aldopentose.
B)L enantiomer;ketopentose.
C)D enantiomer;aldohexose.
D)D enantiomer;ketopentose.

Question 20

A ribopyranose contains ________ carbon atoms while a ribofuranose has ________ carbon atoms.

A)6,5
B)6,6
C)5,6
D)5,5

Question 21

Which are possible conformations of a furanose molecule?

A)Envelope and twist.
B)Chair and boat.
C)Cis and trans.
D)A and B.

Question 22

If glucose supplies the anomeric carbon atom in a glycosidic link,the resulting compound is classified as a ________.

A)glycoside
B)glycan
C)glucoside
D)glucosamine

Question 23

Which statement is false about the sugar units in DNA?

A)They are cyclic in DNA.
B)It is a deoxy form of ribose.
C)It is an epimer of glucose.
D)It has a D-configuration.

Question 24

A reducing sugar is one that

A)contains a b(1→1)link.
B)has a hemiacetal group.
C)can reduce Cu2+ but not Ag+.
D)makes you lose weight.

Question 25

Ribitol is a

A)sugar phosphate.
B)deoxy sugar.
C)amino sugar.
D)sugar alcohol.

Question 26

Naturally occurring glycosides have roles in cells which include

A)building blocks of DNA.
B)chemical signals to plants.
C)food flavoring.
D)units in cell membrane structure.
E)All of the above.

Question 27

What is the name of the disaccharide shown below that is formed by joining two monomers of D-glucose?

A)β-D-glucopyranosyl-(1→4)-β-D-glucopyranose.
B)α-D-glucopyranosyl-(1→4)-α-D-glucopyranose.
C)β-D-glucofuranosyl-(1→4)-β-D-glucofuranose.
D)α-D-glucopyranosyl-(1→3)-β-D-glucopyranose.

Question 28

Which classification(s)is(are)applicable to maltose?

A)Nonreducing sugar.
B)Reducing sugar.
C)Peptidoglycan.
D)Glucoside.
E)Both B and D.

Question 29

The abbreviation for glucose is ________.

A)Glu
B)Gcs
C)Glc
D)Gluc

Question 30

A monosaccharide whose anomeric carbon atom has a glycosidic bond to an alcohol,amine or thiol is a ________.

A)glycoside
B)glycoprotein
C)heteroglycan
D)glucoconjugate

Question 31

The chemical name for table sugar is ________ and it is a ________.

A)lactose;monosaccharide
B)lactose;disaccharide
C)sucrose;monosaccharide
D)sucrose;disaccharide

Question 32

Hydrolysis of maltose will yield ________.

A)glucose and galactose
B)fructose and glucose
C)glucose and mannose
D)glucose only

Question 33

What type of bond links the monomers of a polysaccharide?

A)Glucotide bond.
B)Phosphate ester bond.
C)Peptide bond.
D)Glycosidic bond.

Question 34

Ribitol is a sugar alcohol that is a component of

A)vitamin C.
B)RNA.
C)FMN and FAD.
D)NAD and NADH.
E)sialic acid.

Question 35

Monosaccharide derivatives in which an amino group replaces one of the hydroxyl groups may have important roles in

A)DNA structure.
B)intermediary metabolisms.
C)vitamin C.
D)sialic acids.
E)All of the above.

Question 36

The structure of a disaccharide is shown below.Which statement applies?

A)Both rings A and B are in equilibrium with an open chain form.
B)Only ring A is in equilibrium with an open chain form.
C)Only ring B is in equilibrium with an open chain form.
D)Neither ring is in equilibrium with an open chain form.

Question 37

Who received a Nobel Prize in 1937 for his work on the structures of carbohydrates and the synthesis of Vitamin C?

A)Linus Pauling.
B)Walter Haworth.
C)Max Perutz.
D)Emil Fisher.

Question 38

What distinguishes an aldonic acid from an alduronic acid?

A)The oxidation of the aldehyde group in an aldonic acid and the oxidation of the highest numbered carbon in the alduronic acid.
B)Aldonic acids are derivatives of aldoses,alduronic acids are derivatives of ketoses.
C)Aldonic acids are oxidized forms of linear monosaccharides;alduronic acids are oxidized forms of cyclic monosaccharides.
D)The two terms are synonyms and are used interchangeably.

Question 39

Pyranose rings are usually most stable when the ring adopts a ________ conformation with the bulkiest ring substituents in ________ positions.

A)chair;equatorial
B)chair;axial
C)boat;equatorial
D)boat;axial

Question 40

You have two bottles,each of which contains a white,crystalline substance.Your lab director tells you that one contains lactose and the other sucrose.Your job is to determine which bottle contains which sugar.Which procedure would you use?

A)Test both for solubility in water.Sucrose is very soluble;lactose is only minimally soluble.
B)Test for the ability to reduce Ag+.Only lactose will react.
C)Dissolve each in water and record the pH.Lactose is far more acidic than sucrose.
D)React each with bromine (Br₂)water.Only sucrose will react.

Question 41

Enzymes in the human intestine which are needed to degrade plant starch into limit dextrin are

A)α-Amylase.
B)β-Amylase.
C)debranching enzymes.
D)A and B.
E)A,B,and C.

Question 42

Highly branched cores of amlyopectin that are resistant to hydrolysis are called ________.

A)core saccharides
B)non-reducing saccharides
C)dextran
D)limit dextrins

Question 43

Which is a difference between maltose and cellobiose?

A)One is in cellulose and the other in starch.
B)One is linear and the other is branched.
C)The glycosidic bond is different.
D)The subunit sugars are not glucose for both.
E)All of the above.

Question 44

The elasticity and resistance to compression of connective tissue is due to

A)the branching of the glycosaminoglycans there.
B)the glycosidic linkage to the serine of proteins in the glycosaminoglycans.
C)the carboxyl and sulfated groups in the glycosaminoglycans.
D)the rigid structure of the glycosaminoglycans.
E)All of the above.

Question 45

Which is not a similarity between glycogen and amylopectin?

A)They each contain about 6000 glucose residues.
B)Each has one reducing end and many nonreducing ends.
C)Each is highly branched.
D)Each has branches of similar chain length.

Question 46

Humans can digest limit dextrin that is formed from dietary plant starch using

A)α-amylase.
B)β-amylase.
C)debranching enzyme.
D)A and B.
E)A,B,and C.

Question 47

The bacterial cell wall is sensitive to penicillin because it

A)blocks the linkage of the MurNAc and GlcNAc subunits.
B)blocks the pentaglycine bridge cross linkage.
C)binds to an enzyme which recognizes D-alanine-D-alanine dipeptide.
D)is not attacked by enzymes in animal cells.
E)All of the above.

Question 48

Amylase is a hydrolase that is an ________.

A)endonuclease
B)endoglycosidase
C)exonuclease
D)exoglycosidase that removes maltose
E)exoglycosidase that removes glucose monomers

Question 49

Amylose differs from amylopectin in that amylose

A)has different monomers than amylopectin.
B)has more glucose residues than amylopectin.
C)is highly branched and amylopectin is not.
D)forms a helix and no branch points.

Question 50

Polysaccharide structure can be varied by differences in

A)chain length (number of sugars in each polysaccharide).
B)the kind(s)of sugars in each polysaccharides.
C)the presence of branching.
D)All of the above.

Question 51

Nodulation factors are ________.

A)polysaccharides that help maintain the integrity of tree bark
B)lipo-oligosaccharides that stimulate the growth of nitrogen-fixing structures in plants
C)polysaccharides used to store energy in the roots of plants
D)lipo-saccharides that are often found in tumors

Question 52

________ contain NeuNAc residues and sulfated sugars,and their negative charges contribute to the viscosity of mucins.

A)Proteoglycans
B)N-linked polysaccharides
C)O-linked polysaccharides
D)Hyaluronic acid
E)All of the above

Question 53

Most of the carbohydrates on earth are produced by photosynthesis in plants.

Question 54

The main reasons that glycoproteins are so diverse when compared to other proteoglycans are

A)they may contain different sugars in different combinations and chain lengths.
B)β or α-glycosidic linkages may join various carbon atoms in the sugars.
C)they are found in both bacterial,plant and animal cells.
D)A and B.
E)All of the above.

Question 55

Chitin is

A)found in insect and crustacean shells.
B)found in fungi cell walls.
C)composed of N-acetylglucosamine subunits.
D)composed of linear fibrils like cellulose.
E)All of the above.

Question 56

Termites and cows have bacteria in their digestive tracts that can obtain glucose from plant cellulose because they have enzymes that can attack

A)α-D-glucoside.
B)β-D-glucoside.
C)cellulose branch points.
D)hydrogen bonds in cellulose fibrils.

Question 57

When a sugar polymer is analyzed and found to have equal portions of reducing and non-reducing ends,it is likely that

A)it shows directionality.
B)it is linear.
C)it is branched.
D)it is branched,but not very highly.
E)some of the internal glycosidic bonds are in equilibrium with open chain forms.

Question 58

Both amylose and amylopectin molecules isolated from plant cells can contain as many as ________ glucose residues.

A)25
B)500
C)1000
D)2000
E)6000

Question 59

The major proteoglycan in cartilage is ________.

A)hyaluronic acid
B)cellobiose
C)link protein
D)aggrecan

Question 60

Cellulose is not highly branched because it

A)does not have a polysaccharide backbone.
B)does not have α(1→6)linkages.
C)does not have β(1→4)linkages.
D)is insoluble in water.

Question 61

The simplest aldose is the chiral molecule glyceraldehyde.

Question 62

Furanoses have more three-dimensional conformations than pyranoses.

Question 63

The chair conformation of furanoses is generally preferred to minimize steric repulsion.

Question 64

In solution only one anomeric form of a monosaccharide will be present.

Question 65

Steric strain is a major factor in determining the conformations of a monosaccharide that predominate in solution.

Question 66

Vitamin C is an enediol of a lactone and is vital in the synthesis of collagen.

Question 67

Homoglycans are used for storage,while heteroglycans are used for cell structure.

Question 68

Sugar alcohols do not have a carbonyl group.

Question 69

The ketohexoses have fewer chiral carbon atoms than the aldohexoses.

Question 70

All D-enantiomers of carbohydrates are dextrorotatory.

Question 71

DNA could be referred to as a glycoside.

Question 72

All carbohydrates have the empirical formula (CH₂O)n.

Question 73

For cattle,cellulose is a storage homoglycan.

Question 74

Enzymes that hydrolyze cellulose cannot hydrolyze amylopectin.

Question 75

Both nucleotides and nucleosides are glycosides.

Question 76

The main difference between structures of amylopectin and glycogen is the specific sugar subunit.

Question 77

The sugar derivative found in DNA is an oxidized form of ribose.

Question 78

The reaction between one molecule of alcohol and one molecule of aldehyde yields an acetal.

Question 79

α-amylases hydrolyze α(1→4)linkages and β-amylases hydrolyze β(1→4)linkages,but neither attack α1→6)linkages.

Question 80

Cellulose cannot be degraded in cattle.