Deck 22: Carbohydrates

Question 1

When the name of a monosaccharide is preceded only by (+),it can be said,correctly,that:

A)The compound is the α-anomer.
B)The compound exists in the pyranose form.
C)The compound is dextrorotatory.
D)The compound has the same stereochemistry at the penultimate carbon as d-(+)-glucose.
E)The compound exists only in open-chain form.

Answer 1

The compound is dextrorotatory.

Question 2

What compounds (other than methanol)would be formed in the solution if the glycoside presented below was treated with dilute aqueous hydrochloric acid and the solution allowed to stand?

A)I and II
B)I and III
C)II and III
D)I,III,and IV
E)II,III,and IV

Answer 2

I,III,and IV

Question 3

Which of these is α-d-glucopyranose?

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

Answer 3

I

Question 4

Which of the following structures represent enantiomers?

A)I and II
B)II and III
C)III and IV
D)III and V
E)IV and V

Question 5

Which of the following is an l-aldotetrose?

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

Question 6

Consider the structures shown below.Which structure represents $\beta$ -d-glucopyranose?

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

Question 7

What are the correct designations for the stereogenic centers in this aldose:

A)2R,3S,4R
B)2R,3S,4S
C)2S,3R,4R
D)2S,3S,4R
E)2R,3R,4S

Question 8

Which would undergo mutarotation in neutral aqueous solution?

A)I
B)II
C)III
D)IV
E)I,II and III

Question 9

Sugars that undergo mutarotation in neutral aqueous solution are:

A)I and III
B)III and IV
C)II,III,and IV
D)I,II,and V
E)I and IV

Question 10

Which are the anomers?

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

Question 11

What are carbohydrates?

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

Question 12

What compounds are formed upon oxidation of glucose?

A)CO₂,H₂O,CH₃OH
B)CH₂OH(CHOH)₄COOH
C)CO,H₂O
D)CO₂,H₂O
E)C₆H₁₂O₆

Question 13

Which of the following is a d-aldotetrose?

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

Question 14

Which reagent would cause the following conversion to take place?

A)Excess CH₃OH and KOH
B)Excess CH₃OH and HCl
C)Excess (CH₃)₂SO₄ and OH^-
D)Excess CH₃I and H₃O⁺
E)Excess (CH₃CO)₂O

Question 15

Which of these is a glycoside?

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

Question 16

Which is a ketohexose?

A)d-Glucose
B)d-Fructose
C)d-Mannose
D)d-Ribose
E)(+)-Sucrose

Question 17

Which reagent would be used for the following transformation?

A)CH₃I,KOH
B)
C)CH₃OH,HCl
D)(CH₃)₂SO₄,NaOH
E)

Question 18

How many stereoisomers of the l series would exist for the following pentose? O=CHCHOHCHOHCHOHCH₂OH

A)2
B)3
C)4
D)5
E)8

Question 19

Refer to the structures below.Which are l-sugars?

A)II and IV
B)I,II,and III
C)I and V
D)III,IV,and V
E)IV and V

Question 20

A glycoside is a compound which contains the structural features of these classes of organic compounds:

A)Aldehydes and alcohols
B)Acetals and alcohols
C)Hemiacetals and alcohols
D)Ketones and alcohols
E)Alcohols and carboxylic acids

Question 21

Which of these compounds,I,II,III,IV,is a reducing disaccharide?

A)I alone
B)II alone
C)III alone
D)IV alone
E)I,II,III,and IV

Question 22

Which of the following would give a positive test with Benedict's solution?

A)I
B)II
C)III
D)IV
E)All of these choices.

Question 23

Consider the structures shown below.Which compound is not a reducing sugar?

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

Question 24

Which compound will not reduce Ag(NH₃)₂⁺ ?

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

Question 25

Which reagent would be used for the following transformation?

A)Ag(NH₃)₂⁺
B)HNO₃
C)Br₂/H₂O
D)HCl
E)Ag(NH₃)₂⁺ and Br₂/H₂O

Question 26

An aldonic acid is represented by:

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

Question 27

Which of these is a non-reducing monosaccharide?

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

Question 28

How the tautomerization of a carbohydrate could be prevented?

A)Perform a Fischer methylation of the anomeric OH group.
B)Perform permethylation of the carbohydrate.
C)Treat the carbohydrate with LiAlH₄.
D)Prepare a solution of the carbohydrate in Br₂/H₂O
E)It is impossible to prevent tautomerization.

Question 29

Which of these pyranose forms of an aldohexose can react with two equivalents of acetone in the presence of acid ?

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

Question 30

Which of the following substances will afford a meso product upon reaction with Br₂/H₂O?

A)I
B)II
C)III and IV
D)II,III and IV
E)None of these choices.

Question 31

An aldaric acid is represented by:

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

Question 32

Which is an l-monosaccharide that would yield an optically active aldaric acid on oxidation by nitric acid?

A)I
B)II
C)III
D)II and IV
E)V

Question 33

Refer to the structures below.Which sugar(s)would yield an optically active aldaric acid on oxidation with nitric acid?

A)I and III
B)I,II,III,and V
C)II
D)III and IV
E)I and V

Question 34

What of the following reagents will permethylate a carbohydrate?

A)Acetone
B)CH₃OSO₃CH₃
C)H₂/Pd
D)Acetic anhydride
E)CH₃OH/HCl

Question 35

Which aldohexose would yield an optically active aldaric acid when treated with nitric acid?

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

Question 36

Consider the structures below.Which monosaccharides would yield an optically active aldonic acid when oxidized with bromine water?

A)I,II,and III
B)I,II,and V
C)III,IV,and VI
D)II,III,and IV
E)All of these choices.

Question 37

Reaction of the following substance with nitric acid would yield:

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

Question 38

Reaction of the following substance with bromine water would yield:

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

Question 39

Which of these is a component of the mixture formed when d-galactose is placed in aqueous base (de Bruyn-van Ekenstein transformation)?

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

Question 40

What reagents could be used to selectively protect the HO groups at positions 1 and 6 of a hexose?

A)TBDPS-Cl,AgNO₃ followed by acetic anhydride.
B)CH₃OH/HCl followed by TBDPS-Cl.
C)CH₃CO₂H,HCl followed by (CH₃)₃C(C₆H₅)₂-SiCl.
D)Acetic anhydride followed by acetone.
E)Benzaldehyde followed by CH₃OH/HCl.

Question 41

Consider the structures below.Which of the structures II-VI are epimers of I?

A)II
B)III and IV
C)IV
D)V
E)VI

Question 42

A d-aldohexose X,is subjected to a Ruff degradation.The degradation product is treated with nitric acid to yield an optically inactive aldaric acid.A possible structure for X is:

A)I
B)II
C)III and IV
D)IV
E)II and V

Question 43

What is the ratio of products formed by the reaction of periodic acid with the following compound? H₂C=O HCO₂H CO₂ I 5 1 0
II 3 3 0
III 1 5 0
IV 1 4 1
V 0 4 2

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

Question 44

An unknown pentose Z reacts with NaBH₄ to give an optically inactive compound.The pentose Z gives the same osazone as arabinose.What carbohydrate is Z?

A)Fructose
B)Ribose
C)Xylose
D)Glucose
E)Lyxose

Question 45

If the methyl glycoside of an aldohexose is treated with HIO₄,one molar equivalent of HCHO is formed but no HCOOH.What size ring is present in the glycoside?

A)Three-membered
B)Four-membered
C)Five-membered
D)Six-membered
E)Seven-membered

Question 46

Reaction of the following substance with sodium borohydride (NaBH₄)would yield:

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

Question 47

Refer to the structures below.Which sugars would react with phenylhydrazine to yield the same phenylosazone?

A)I and II
B)III and IV
C)I and V
D)II and III
E)III and V

Question 48

Which of the following structures represent epimers?

A)I and II
B)III and V
C)III and IV
D)I and III
E)Pairs in more than one of these choices.

Question 49

The Kiliani-Fischer synthesis is the reaction of an aldose with:

A)Br₂/H₂O; then HCN; then H₃O⁺; then Na-Hg,H₂O
B)HCN; then Ba(OH)₂; then H₃O⁺; then Na-Hg,H₂O
C)HCN; then H₃O⁺; then Ba(OH)₂; then Na-Hg,H₂O
D)Br₂/H₂O; then H₂O₂,Fe₂(SO₄)₃
E)Br₂/H₂O

Question 50

Consider the structures above.Which monosaccharides would yield the same phenylosazone when treated with excess phenylhydrazine?

A)I and V
B)I and III
C)II and III
D)III and VI
E)IV and V

Question 51

A compound X reacts with 3 mol of HIO₄ to yield 2 mol of HCO₂H and 2 mol of HCHO.What is the structure of X?

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

Question 52

Which reagent would be used for the following transformation?

A)NaBH₄
B)AgNO₃/C₂H₅OH
C)Br₂/CCl₄
D)HCl
E)Hot KMnO₄

Question 53

Refer to the following structures.Which d-aldohexose would react with NaBH₄ to yield an optically inactive alditol?

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

Question 54

The Ruff degradation is the reaction of an aldose with:

A)Br₂/H₂O; then HCN; then H₃O⁺; then Na-Hg,H₂O
B)HCN; then Ba(OH)₂; then H₃O⁺; then Na-Hg,H₂O
C)HCN; then H₃O⁺; then Ba(OH)₂; then Na-Hg,H₂O
D)Br₂/H₂O; then H₂O₂,Fe₂(SO₄)₃
E)Br₂/H₂O

Question 55

Consider the structures below: what term(s)describe(s)the relationship between them?

A)Enantiomers
B)Epimers
C)Diastereomers
D)Anomers
E)More than one of these choices.

Question 56

Which of the following substances will afford an optically inactive product upon reaction with nitric acid?

A)I
B)II
C)III and IV
D)II,III and IV
E)All of these choices.

Question 57

Epimers are represented by:

A)I and II
B)II and III
C)I,II,and III
D)III and IV
E)I,II,and V

Question 58

Sugars that would yield the same phenylosazone are:

A)I and II
B)II and III
C)I,II,and III
D)III and IV
E)I,II,and V

Question 59

Sucrose reacts with which of these reagents?

A)C₆H₅NHNH₂
B)Cu²⁺
C)Br₂/H₂O
D)H₃O⁺
E)Ag(NH₃)₂⁺

Question 60

What is the ratio of products formed by the reaction of periodic acid with the following compound? H₂C=O HCO₂H CO₂ I 5 1 0
II 3 3 0
III 1 5 0
IV 2 3 1
V 0 4 2

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

Question 61

The d-glucose unit at the branching point of amylopectin has free hydroxyl groups at which positions?

A)C2,C3,and C6
B)C2 and C3
C)C3 and C4
D)C3,C4,and C6
E)C4 and C6

Question 62

Which of these is an example of a glucan?

A)Maltose
B)Sucrose
C)Lactose
D)Cellobiose
E)Amylose

Question 63

Which compound or compounds would be formed when d-glucose is dissolved in methanol and then treated with anhydrous acid?

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

Question 64

Refer to the following structures.Which aldohexose when subjected to Fischer's end-group interchange would be converted to a compound identical with itself?

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

Question 65

Which monosaccharide is recovered from the hydrolysis of starch?

A)d-Galactose
B)d-Gulose
C)d-Glucose
D)Cellobiose
E)Maltose

Question 66

An aldopentose,X,is subjected to a Kiliani-Fischer synthesis to produce two aldohexoses,Y and Z.Both Y and Z,when oxidized with nitric acid,yield optically active aldaric acids.Which structure represents X?

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

Question 67

Which of the following would yield d-glucose and d-mannose when subjected to a Kiliani-Fischer synthesis?

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

Question 68

Which is a reducing sugar with an α-glycosidic linkage?

A)Sucrose
B)Maltose
C)Lactose
D)Cellobiose
E)Glucose

Question 69

Which compound is d-galactose?

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

Question 70

Complete hydrolysis of heparin gives:

A)" $\beta$ -N-Acetylmuramic acid and $\beta$ -d-glucosamine."
B)" $\beta$ -d-Glucosamine and glucuronate-2-sulfate."
C)"d-Glucuronate-2-sulfate and N-sulfo-3-glucosamine-6-sulfate."
D)"Glucose sulfate and maltose.
E)"Chitin and d-glucurunate-2-sulfate."

Question 71

Which monosaccharide is recovered from the hydrolysis of glycogen?

A)d-Galactose
B)d-Glucose
C)d-Gulose
D)Cellobiose
E)Maltose

Question 72

Compound X is a reducing sugar which,on hydrolysis,affords two molar equivalents of d-glucose.This hydrolysis is catalyzed by an enzyme specific for glucosides of this type: What is the identity of X?

A)Sucrose
B)Lactose
C)Maltose
D)Cellobiose
E)None of these choices.

Question 73

A d-aldohexose,Z,is subjected to a Ruff degradation.The degradation product is treated with nitric acid to yield an optically active aldaric acid.A possible structure for Z is:

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

Question 74

What is an amino sugar?

A)A sugar that bears substituted with an amino acid on the anomeric OH group.
B)An amino acid with a side chain as a sugar.
C)A sugar where the anomeric OH group is substituted by an ammonium group.
D)A sugar where a non-anomeric OH group is replaced by an amino group.
E)An amino acid replacing an OH group on a sugar.

Question 75

Consider the structure of d-allose below: Which of the following structures represents l-allose?

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

Question 76

Consider the structures below.An l-aldohexose,X,is treated with nitric acid to yield an optically inactive aldaric acid.The same l-aldohexose,X,is subjected to a Ruff degradation and the degradation product is oxidized with nitric acid to produce an optically inactive aldaric acid.Which is a possible structure for X?

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

Question 77

What is "gun cotton"?

A)Cellulose trinitrate
B)Cellulose acetate
C)Cellulose xanthate
D)Amilose acetate
E)Maltose trinitrate

Question 78

Which of the following is the structure of d-galacturonic acid?

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

Question 79

Which is not an intermediate monosaccharide in the Kiliani-Fischer synthesis of d-mannose from d-glyceraldehyde?

A)d-Ribose
B)d-Threose
C)d-Arabinose
D)d-Erythrose
E)d-Ribose and d-Threose

Question 80

Cellulose lacks nutritive value for humans because:

A)the products of its digestion are excreted without utilization.
B)its conformation prevents attack by digestive enzymes.
C)we lack the enzymes which can catalyze the hydrolysis of the glycosidic linkages.
D)it passes through the digestive tract so rapidly.
E)the molecules possess such a high molecular weight that enzymes can not hydrolyze it.