Deck 26: Carbohydrates

Question 1

Amylose is a polysaccharide with ________ linkages.

A)b-1,4'-glycosidic
B)a-1,4'-glycosidic
C)b-1,6'-glycosidic
D)a-1,6'-glycosidic

Answer 1

a-1,4'-glycosidic

Question 2

Which of the following pairs of carbohydrates will afford the same product from a Wohl degradation?

A)Xylose/glucose
B)Ribose/arabinose
C)Fructose/mannose
D)Lyxose/threose

Answer 2

Ribose/arabinose

Question 3

Which of the following compounds is an aldose?

A)A
B)B
C)C
D)D

Answer 3

B

Question 4

Which of the following compounds is a b anomer?

A)A
B)B
C)C
D)D

Question 5

How many possible stereoisomers are there of the following heptose?

A)16
B)21
C)32
D)64

Question 6

Which of the following reagents will selectively oxidize an aldose to an aldonic acid?

A)PCC
B)Ag₂O in NH₄OH
C)FeCl₃
D)HNO₃

Question 7

Which is the correct Fischer projection for the open-chain form of the carbohydrate shown below?

A)A
B)B
C)C
D)D

Question 8

How many carbons does a pentose sugar have?

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

Question 9

Which is the correct Haworth projection for the banomer of D-glucose?

A)A
B)B
C)C
D)D

Question 10

Which of the following is a reducing sugar?

A)A
B)B
C)C
D)D

Question 11

Is the following carbohydrate D or L? Provide an explanation for your answer.

A)It is D because the OH group on C2 is on the right.
B)It is L because the OH group on C4 is on the left.
C)It is L because the OH group on C3 is on the left.
D)It is D because the sugar is not symmetric.

Question 12

What are the products of the following reaction?

A)A
B)B
C)C
D)D

Question 13

Cellulose is a polysaccharide with ________ linkages.

A)b-1,4'-glycosidic
B)a-1,4'-glycosidic
C)b-1,6'-glycosidic
D)a-1,6'-glycosidic

Question 14

Which is the correct Haworth projection for the aanomer of allose?

A)A
B)B
C)C
D)D

Question 15

What is the correct chair form for the aanomer of D-mannose?

A)A
B)B
C)C
D)D

Question 16

Which of the following compounds is not a valid representation for D-glucose?

A)A
B)B
C)C
D)D
E)E

Question 17

Does a monosaccharide prefer to exist in the open-chain or closed-ring form?

A)Open
B)Closed
C)Both forms exist in equal ratios.

Question 18

Which of the following reagents would convert glucose into ethyl glucopyranoside?

A)EtBr,aq.HCl
B)EtOH,aq.HCl
C)EtOH,NaOH
D)Ag₂O in NH₄OH

Question 19

What is the correct chair form for the banomer of D-glucose?

A)A
B)B
C)C
D)D

Question 20

What is the process called for the interconversion of one anomer to the other?

A)Racemization
B)Mutarotation
C)Epimerization
D)Enolization

Question 21

The branching units in amylopectin,a polysaccharide,which enable this molecule to be water soluble are connected with ________ linkages.

A)b-1,4'-glycosidic
B)a-1,4'-glycosidic
C)a-1,6'-glycosidic
D)b-1,6'-glycosidic

Question 22

From the sugars shown below,which one will not give a positive test with Tollens reagent?

A)A
B)B
C)C
D)D

Question 23

What is the best description of the product formed in the following reaction sequence?

A)The product is an optically active aldonic acid.
B)The product is an optically inactive aldonic acid.
C)The product is an optically active aldaric acid.
D)The product is an optically inactive aldaric acid.

Question 24

Upon hydrolysis of cellulose,what sugar is formed?

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

Question 25

Upon hydrolysis of amylose,what sugar is formed?

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

Question 26

After a series of Kiliani-Fischer syntheses on D-glyceraldehyde,an unknown sugar was isolated from the reaction mixture.The following experimental data was obtained.What is the structure of this unknown sugar? Data:
- Molecular formula: C₆H₁₂O₆
- Reacts with phenylhydrazine to give an osazone,mp 178°C.
- Reacts with HNO₃ to give an optically active aldaric acid.
- Wohl degradation followed by HNO₃ oxidation gives an optically inactive
Aldaric acid.
- Two Wohl degradations followed by HNO₃ oxidation give a meso-tartaric acid.

A)A
B)B
C)C
D)D

Question 27

Which sugar is represented by the line angle structure below?

A)D-fructose
B)D-sorbose
C)L-psicose
D)L-tagatose

Question 28

Upon hydrolysis of amylopectin,what sugar is formed?

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

Question 29

What is the composition of maltose?

A)Two glucose units with a a-1,4'-glycoside bond
B)One glucose and one fructose unit with a a-glycosidic bond to the 2' carbon of a fructofuranose ring
C)One galactose and one glucose unit with a b-1,4'-glycoside bond
D)Repeating unit of glucose units joined in a b-1,4'-glycosidic linkage

Question 30

From the disaccharides listed below,which one will not undergo mutarotation?

A)Sucrose
B)Maltose
C)Lactose
D)Xylobiose

Question 31

Which of the following best describes the relationship between D-glucose and D-fructose?

A)Enantiomers
B)Epimers
C)Anomers
D)Constitutional isomers

Question 32

What is the composition of lactose?

A)Two glucose units with a a-1,4'-glycoside bond
B)One glucose and one fructose unit with a a-glycosidic bond to the 2' carbon of a fructofuranose ring
C)One galactose and one glucose unit with a b-1,4'-glycoside bond
D)Repeating unit of glucose units joined in a b-1,4'-glycosidic linkage

Question 33

Which of the following sugars can be classified as a ketotetrose?

A)A
B)B
C)C
D)D

Question 34

Which of the following sugars can be classified as an aldohexose?

A)A
B)B
C)C
D)D

Question 35

Oxidation of a D-hexose with nitric acid forms an optically active aldaric acid.A Wohl degradation of the same D-hexose followed by oxidation with nitric acid forms an optically active aldaric acid.What are the three possible D-hexoses that fit this data?

A)D-allose,D-altrose and D-glucose
B)D-glucose,D- mannose and D-talose
C)D-glucose,D-idose and D-altrose
D)D-galactose,D-talose and D-mannose

Question 36

Which of the following sugars can be classified as a ketohexose?

A)A
B)B
C)C
D)D

Question 37

What is the composition of sucrose?

A)Two glucose units with a a-1,4'-glycoside bond
B)One glucose and one fructose unit with a a-glycosidic bond to the 2' carbon of a fructofuranose ring
C)One galactose and one glucose unit with a b-1,4'-glycoside bond
D)Repeating unit of glucose units joined in a b-1,4'-glycosidic linkage

Question 38

From the sugars shown below,which one is a non-reducing sugar?

A)A
B)B
C)C
D)D

Question 39

Which of the following sugars can be classified as a ketopentose?

A)A
B)B
C)C
D)D

Question 40

The following reaction is an example of a base-catalyzed epimerization reaction in which a ketose is converted to a pair of aldoses.What are the products from this reaction?

A)D-glucose and D-mannose
B)D-galactose and D-talose
C)D-talose and D-idose
D)D-glucose and D-idose

Question 41

What is the Fischer projection of the monosaccharide from which the following glycoside was prepared?

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

Question 42

Which of the following is D-galactose?

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

Question 43

Which of the following is D-fructose?

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

Question 44

What is the classification of pyranose forms of monosaccharides?

A)5-Membered cyclic hemiacetals
B)6-Membered cyclic acetals
C)5-Membered cyclic acetals
D)6-Membered cyclic hemiacetals

Question 45

Which of the following is a disaccharide?

A)Maltose
B)Lactose
C)Sucrose
D)All of these choices are correct

Question 46

Which of the following is D-sorbose?

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

Question 47

What is the Haworth projection of the α anomer of a monosaccharide epimeric with D-glucose at C3?

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

Question 48

What is the Fischer projection of the monosaccharide from which the following glycoside was prepared?

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

Question 49

Which of the following is D-glucose?

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

Question 50

Which of the following is a polysaccharide?

A)Cellulose
B)Starch
C)Glycogen
D)All of these choices are correct