Deck 25: Biomolecules: Carbohydrates

Question 1

Exhibit 25-6
Refer to the sugars below to answer the following question(s).Choose the sugar that best fits each description and place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question,but sugars may be used more than once.
_____ oxidizes to an optically inactive aldaric acid

Answer 1

c

Question 2

Exhibit 25-4
From the sugars below,choose the one that best fits each description below.Place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question.
_____ a deoxy sugar.

Answer 2

b

Question 3

Exhibit 25-4
From the sugars below,choose the one that best fits each description below.Place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question.
_____ a sugar which yields a single alditol upon reduction.

Answer 3

b

Question 4

Exhibit 25-4
From the sugars below,choose the one that best fits each description below.Place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question.
Refer to Exhibit 25-4.Name sorbose systematically.

Question 5

Exhibit 25-5
Refer to the equilibrium below to answer the following question(s).
Refer to Exhibit 25-5.Classify ribose by carbonyl type and number of carbons.

Question 6

Exhibit 25-4
From the sugars below,choose the one that best fits each description below.Place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question.
Refer to Exhibit 25-4.Provide the complete name for the α-anomer of rhamnose in its pyranose form.

Question 7

Exhibit 25-6
Refer to the sugars below to answer the following question(s).Choose the sugar that best fits each description and place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question,but sugars may be used more than once.
_____ a D-ketohexose

Question 8

Exhibit 25-4
From the sugars below,choose the one that best fits each description below.Place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question.
Refer to Exhibit 25-4.Draw both chair conformations of the α-anomer of rhamnose in its pyranose form.Circle the more stable conformation.

Question 9

Exhibit 25-4
From the sugars below,choose the one that best fits each description below.Place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question.
Refer to Exhibit 25-4.Assign R or S configuration to each chirality center in sorbose.

Question 10

Exhibit 25-5
Refer to the equilibrium below to answer the following question(s).
Refer to Exhibit 25-5.The correct name for the cyclic structure is _______.

A)α-L-ribofuranose
B)β-D-ribofuranose
C)α-L-ribopyranose
D)β-D-ribopyranose

Question 11

Exhibit 25-5
Refer to the equilibrium below to answer the following question(s).
Refer to Exhibit 25-5.Which enantiomer of ribose is drawn,D or L?

Question 12

Exhibit 25-3
Refer to the monosaccharides below to answer each of the following question(s): Classify each sugar by type;for example,glucose is an aldohexose.
Refer to Exhibit 25-3.Sorbose is _____.

Question 13

Exhibit 25-3
Refer to the monosaccharides below to answer each of the following question(s): Classify each sugar by type;for example,glucose is an aldohexose.
Refer to Exhibit 25-3.Xylulose is _____.

Question 14

Exhibit 25-4
From the sugars below,choose the one that best fits each description below.Place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question.
_____ a sugar with three chirality centers.

Question 15

Exhibit 25-2
Label each pair of stereoisomers below as:
_____

A)enantiomers
B)diastereomers
C)identical
Place the letter of the correct answer in the blank to the left of the pair of stereoisomers.

Question 16

Exhibit 25-2
Label each pair of stereoisomers below as:
_____

A)enantiomers
B)diastereomers
C)identical
Place the letter of the correct answer in the blank to the left of the pair of stereoisomers.

Question 17

Exhibit 25-4
From the sugars below,choose the one that best fits each description below.Place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question.
_____ a D-sugar.

Question 18

Draw a Fischer projection of (2R,3S)-dibromobutane.

Question 19

Exhibit 25-2
Label each pair of stereoisomers below as:
_____

A)enantiomers
B)diastereomers
C)identical
Place the letter of the correct answer in the blank to the left of the pair of stereoisomers.

Question 20

Exhibit 25-3
Refer to the monosaccharides below to answer each of the following question(s): Classify each sugar by type;for example,glucose is an aldohexose.
Refer to Exhibit 25-3.Erythrulose is _____.

Question 21

Exhibit 25-8
Draw structures for the products you would expect to obtain from reaction of β-D-galactopyranose with each of the following reagents.Be sure to include all relevant stereochemistry. β-D-galactopyranose
CH₃OH,HCl

Question 22

Exhibit 25-10
Choose a structure from the list provided below that best fits each of the following descriptions.Place the letter of the structure in the blank to the left of the description.There is only one correct answer for each question.
a.starch
b.cellulose
c. d. e. f.sucrose
_____ a monosaccharide that gives a negative Benedict's Test.

Question 23

Exhibit 25-10
Choose a structure from the list provided below that best fits each of the following descriptions.Place the letter of the structure in the blank to the left of the description.There is only one correct answer for each question.
a.starch
b.cellulose
c. d. e. f.sucrose
_____ a disaccharide

Question 24

Exhibit 25-8
Draw structures for the products you would expect to obtain from reaction of β-D-galactopyranose with each of the following reagents.Be sure to include all relevant stereochemistry. β-D-galactopyranose
CH₃I,Ag₂O

Question 25

Exhibit 25-8
Draw structures for the products you would expect to obtain from reaction of β-D-galactopyranose with each of the following reagents.Be sure to include all relevant stereochemistry. β-D-galactopyranose
NaOCH₃

Question 26

Exhibit 25-8
Draw structures for the products you would expect to obtain from reaction of β-D-galactopyranose with each of the following reagents.Be sure to include all relevant stereochemistry. β-D-galactopyranose
H₃O⁺

Question 27

Exhibit 25-8
Draw structures for the products you would expect to obtain from reaction of β-D-galactopyranose with each of the following reagents.Be sure to include all relevant stereochemistry. β-D-galactopyranose
Br₂,H₂O

Question 28

What is the correct structure for α-D-glucopyranose?

A)
B)
C)
D)

Question 29

Exhibit 25-9
Choose a structure from the list provided below that best fits each of the following descriptions.Place the letter of the structure in the blank to the left of the description.There is only one correct answer for each question.
A. B. C. D. E. F.
_____ a reducing monosaccharide

Question 30

The Fischer projection for D-iodose corresponds to which pyranose below?

A)
B)
C)
D)

Question 31

Exhibit 25-8
Draw structures for the products you would expect to obtain from reaction of β-D-galactopyranose with each of the following reagents.Be sure to include all relevant stereochemistry. β-D-galactopyranose
warm dilute HNO₃

Question 32

Exhibit 25-8
Draw structures for the products you would expect to obtain from reaction of β-D-galactopyranose with each of the following reagents.Be sure to include all relevant stereochemistry. β-D-galactopyranose
NaBH₄ in H₂O

Question 33

Exhibit 25-9
Choose a structure from the list provided below that best fits each of the following descriptions.Place the letter of the structure in the blank to the left of the description.There is only one correct answer for each question.
A. B. C. D. E. F.
_____ amylopectin

Question 34

Exhibit 25-10
Choose a structure from the list provided below that best fits each of the following descriptions.Place the letter of the structure in the blank to the left of the description.There is only one correct answer for each question.
a.starch
b.cellulose
c. d. e. f.sucrose
_____ a β-1,4'-glycoside

Question 35

Exhibit 25-9
Choose a structure from the list provided below that best fits each of the following descriptions.Place the letter of the structure in the blank to the left of the description.There is only one correct answer for each question.
A. B. C. D. E. F.
_____ a 1,4' β-glycoside

Question 36

Exhibit 25-9
Choose a structure from the list provided below that best fits each of the following descriptions.Place the letter of the structure in the blank to the left of the description.There is only one correct answer for each question.
A. B. C. D. E. F.
_____ a non-reducing disaccharide

Question 37

Exhibit 25-6
Refer to the sugars below to answer the following question(s).Choose the sugar that best fits each description and place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question,but sugars may be used more than once.
_____ a ketose with two chirality centers

Question 38

Exhibit 25-9
Choose a structure from the list provided below that best fits each of the following descriptions.Place the letter of the structure in the blank to the left of the description.There is only one correct answer for each question.
A. B. C. D. E. F.
_____ cellulose

Question 39

Exhibit 25-8
Draw structures for the products you would expect to obtain from reaction of β-D-galactopyranose with each of the following reagents.Be sure to include all relevant stereochemistry. β-D-galactopyranose
(CH₃CO)₂O,pryridine

Question 40

Exhibit 25-6
Refer to the sugars below to answer the following question(s).Choose the sugar that best fits each description and place the letter of the sugar in the blank to the left of the description.There is only one correct answer for each question,but sugars may be used more than once.
_____ a dextrorotary hexose

Question 41

Exhibit 25-11
Consider the reaction below to answer the following question(s).
Refer to Exhibit 25-11.Place a triangle around the anomeric carbon in compound Q.

Question 42

Exhibit 25-11
Consider the reaction below to answer the following question(s).
Refer to Exhibit 25-11.Which anomer is the LEAST stable?
Q or Z

Question 43

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Question 44

Exhibit 25-11
Consider the reaction below to answer the following question(s).
Refer to Exhibit 25-11.Compound Z is:

A)the D-anomer.
B)the α-anomer.
C)the β-anomer.
D)the L-anomer.

Question 45

Compound U is an aldotetrose that can be oxidized to an optically active aldaric acid,compound V.Upon Wohl degradation,compound U is converted into D-glyceraldehyde.Upon Kiliani-Fischer chain extension,compound U is converted into compounds W and X.Compound W can be oxidized to an optically inactive aldaric acid,compound Y,but compound X is oxidized to an optically active aldaric acid Z.What are the structures of compounds U-Z?

Question 46

Examine the following molecular models.Atoms other than carbon and hydrogen are labeled. ​
​ ​
​
Which of the following correctly describes these substances?

A)Equivalent structures
B)Enantiomers
C)Diastereomers
D)Constitutional isomers

Question 47

Exhibit 25-11
Consider the reaction below to answer the following question(s).
Refer to Exhibit 25-11.Q and Z are cyclic examples of:

A)acetals
B)hemiacetals
C)alditols
D)hemialditols

Question 48

Exhibit 25-12
Below is the structure of the antigenic determinant for the blood group B.Use this structure to answer the following question(s).
Refer to Exhibit 25-12.Put a BOX around the 1,3'-glycosidic linkage.

Question 49

For a hypothetical aldoheptose with 5 chirality centers,how many stereoisomers are possible?

A)4
B)8
C)16
D)32
E)64

Question 50

This cyclization is an example of an intramolecular nucleophilic addition of an alcohol with an aldehyde.This process is catalyzed by mild acid.On the structures provided below draw arrows indicating electron flow in this reaction mechanism.

Question 51

Exhibit 25-11
Consider the reaction below to answer the following question(s).
Refer to Exhibit 25-11.The process by which anomer Q is converted into a mixture of both anomers is called:

A)anomeric rotation.
B)glycosidation.
C)pyranorotation.
D)mutarotation.

Question 52

In comparing Fischer projections,which of the following are allowed rotations in the plane of the page?

A)90°
B)180°
C)270°
D)a and c
E)a,b and c

Question 53

Examine the following molecular models.Atoms other than carbon and hydrogen are labeled. ​
​ A B
​
​
Which of the following correctly describes these substances?

A)A is a D sugar and B is an L sugar
B)A is an L sugar and B is a D sugar
C)Both are D sugars.
D)Both are L sugars.

Question 54

Consider the following structure.Atoms other than carbon and hydrogen are labeled. How many chirality centers are present?

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

Question 55

Consider the following structure.Atoms other than carbon and hydrogen are labeled. Which of the following is not a correct classification for this substance?

A)Aldose
B)Pentose
C)Nonreducing sugar
D)Monosaccharide
E)All are correct classifications.

Question 56

Fructose reduces Tollens' reagent even though it contains no aldehyde group.This occurs because fructose is readily isomerized to an aldose in basic solution.Write the complete stepwise mechanism for the base-catalyzed isomerization of fructose to an aldohexose.Show all intermediate structures and all electron flow with arrows.

Question 57

Classify the following substance.Atoms other than carbon and hydrogen are labeled.

A)
B)
C)
D)

Question 58

What relationships exists between the following two substances? Atoms other than carbon and hydrogen are labeled. ​
​ ​
​

A)Identical
B)Enantiomers
C)Anomers
D)Meso compounds

Question 59

Exhibit 25-12
Below is the structure of the antigenic determinant for the blood group B.Use this structure to answer the following question(s).
Refer to Exhibit 25-12.One of the monosaccharides is an unusual deoxy sugar called L-fucose.CIRCLE the L-fucose moiety.

Question 60

Melibiose is a reducing disaccharide that forms D-glucose and D-galactose on hydrolysis.Reaction of melibiose with iodomethane and silver oxide yields an octamethyl derivative,which can be hydrolyzed with aqueous acid to give one equivalent of 2,3,4,6-tetra-O-methyl-D-galactopyranose and one equivalent of 2,3,4,-tri-O-methyl-D-glucopyranose.If melibiose contains an α-glycosidic bond,what is its structure?
​

Question 61

Which of the following is correct as applies to the essential carbohydrates?

A)Cannot be synthesized by metabolic pathways
B)Simple aldohexoses
C)Arise from glucose or galactose
D)Synthesis is highly endergonic

Question 62

Consider the following reaction sequence.
1 ) HCN
2 ) H₂/Pd
3 ) H₃O⁺
The result of this treatment to a monosaccharides would be:

A)oxidation of the carbonyl group
B)lengthening the carbon chain by one carbon atom
C)shortening the carbon chain by one carbon atom
D)formation of a glycoconjugate

Question 63

The intermediate common to both chain lengthening and shortening of a simple sugar is a(n):

A)imine.
B)oxime.
C)enamine.
D)cyanohydrin.