Deck 21: Biomolecules: Carbohydrates

Question 1

Instructions: Refer to the sugars below to answer the following question(s).Choose the sugar that best fits each description.There is only one correct answer for each question,but sugars may be used more than once.Indicate each answer by the corresponding letter.


Refer to instructions._____ a ketose and _____ an aldose with two chirality centers

A)a
B)b
C)c
D)d

Answer 1

c
d

Question 2

Instructions: Refer to D-iodose below to answer the following question(s).
Refer to instructions.The Fischer projection for D-iodose (above)corresponds to which pyranose below?

A)
B)
C)
D)

Answer 2

Question 3

Instructions: Refer to the monosaccharides below to answer the following question(s).


Refer to instructions.Provide the complete name for the a-anomer of rhamnose in its pyranose form.

Answer 3

a-L-Rhamnopyranose

Question 4

If the following compound undergoes oxidation in the presence of the appropriate enzyme,draw the structure of the likely product.

Question 5

Draw the Fisher projection of L-mannose.

Question 6

Instructions: Refer to the equilibrium below to answer the following question(s).


Refer to instructions.Which enantiomer of ribose is drawn,D or L,and is it the a or b anomer?

Question 7

Convert the following Fisher projections into tetrahedral representations.

Question 8

Instructions: Refer to the monosaccharides below to answer the following question(s).Classify each sugar by type;for example,glucose is an aldohexose.


Refer to instructions.Erythrulose is ____________________.

Question 9

Instructions: Refer to the equilibrium below to answer the following question(s).


Refer to instructions.Classify ribose by carbonyl type and number of carbons.

Question 10

Instructions: Refer to the monosaccharides below to answer the following question(s).


Refer to instructions.Assign R or S configuration to each chirality center in sorbose.

Question 11

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

A)
B)
C)
D)

Question 12

Using the following structure of D-talose as a guide,draw the structure for a-D-talopyranose.Label each ring substituent as axial or equatorial.

Question 13

Instructions: Refer to the equilibrium below to answer the following question(s).
Refer to instructions.The correct name for the cyclic structure is____.

A)a-L-ribofuranose
B)b-D-ribofuranose
C)a-L-ribopyranose
D)b-D-ribopyranose

Question 14

Instructions: Refer to the monosaccharides below to answer the following question(s).


Refer to instructions.Draw both chair conformations of the a-anomer of rhamnose in its pyranose form.Circle the more stable conformation.

Question 15

Instructions: Refer to the sugars below to answer the following question(s).Choose the sugar that best fits each description.There is only one correct answer for each question,but sugars may be used more than once.Indicate each answer by the corresponding letter.


Refer to instructions._____ a dextrorotary hexose and ______ a levorototary tetrose.

A)a
B)b
C)c
D)d

Question 16

Instructions: Refer to the sugars below to answer the following question(s).Choose the sugar that best fits each description.There is only one correct answer for each question,but sugars may be used more than once.Indicate each answer by the corresponding letter.


Refer to instructions._____ oxidizes to an optically inactive aldaric acid.

A)a
B)b
C)c
D)d

Question 17

The specific rotation of the pure a-anomer of a monosaccharide is +169.7 and that of the pure b-anomer is +29.4.A solution of the pure a-anomer produces a specific rotation of +61.4.Based on this data,which of the following is correct?

A)The solution contains more of the a-anomer.
B)The solution is an equimolar mixture of the two anomers.
C)A solution of the pure b-anomer would produce the same specific rotation.
D)The change in specific rotation is due to the irreversible formation of the open-chain monosaccharide.
E)All of these.

Question 18

Draw the structure of the product of the following reaction.

Question 19

Instructions: Refer to the monosaccharides below to answer the following question(s).Classify each sugar by type;for example,glucose is an aldohexose.


Refer to instructions.Sorbose is ____________________.

Question 20

Complete the equation for the following reaction.

Question 21

Instructions: Consider the reaction below to answer the following question(s).

Refer to instructions.Place a triangle around the anomeric carbon in compound Q.

Question 22

How many D-ketotetroses could exist?

A)none
B)one
C)two
D)four
E)eight

Question 23

Instructions: Consider the reaction below to answer the following question(s).


Refer to instructions.Which anomer is the LEAST stable?
Q or Z

Question 24

Which of the following has a D-configuration?

A)only 1 and 2
B)only 1 and 3
C)only 2 and 3
D)only 1,2 and 3

Question 25

What is the relationship between D-erythrose and D-threose?

A)they are constitutional isomers
B)they are enantiomers
C)they are diastereomers
D)they are tautomers

Question 26

Instructions: Choose a structure from the list provided below that best fits the description given.There is only one correct answer for each question.

Question 27

Aldohexoses may exist as furanoses or pyranoses.Aldopentoses also may exist as furanoses or pyranoses.

Question 28

The brick-red color observed when Benedict's test is applied to D-mannose is due to

A)the reduced form of the Cu²⁺ reagent
B)the reduced form of the D-mannose
C)the oxidized form of the Cu²⁺ reagent
D)the oxidized form of the D-mannose
E)products in the mixture other than those listed

Question 29

Refer to the carbohydrate below to answer the following questions.

a) Which carbon in the carbohydrate is the anomeric carbon?
b) Does this represent an a or b-anomoer?

Question 30

The monosaccharide shown below is

A)an aldohexose
B)an aldopentose
C)an aldotetrose
D)a ketohexose
E)a ketopentose

Question 31

Draw an aldopentose with S,S,R stereochemistries at its carbons 2 through 4.

Question 32

Instructions: Draw structures for the products you would expect to obtain from reaction of b-D-galactopyranose with the listed reagents.Be sure to include all relevant stereochemistry.
b-D-galactopyranose
Draw:
Ch₃I,Ag₂O

Question 33

Refer to the carbohydrate below to answer the following questions.

a) Which carbon in the carbohydrate is the anomeric carbon?
b) What would be observed on the addition of Tollen's reagent to a solution of this sugar?

Question 34

Instructions: Draw structures for the products you would expect to obtain from reaction of b-D-galactopyranose with the listed reagents.Be sure to include all relevant stereochemistry.
b-D-galactopyranose
Draw:
NaBH₄ in H₂O

Question 35

Which of the following could not form a pyranose?

A)D-threose
B)D-ribose
C)D-lyxose
D)D-glucose
E)D-galactose

Question 36

Treatment with dilute NaOH can convert

A)an aldose into a ketose
B)an aldose into a carboxylic acid
C)an aldose into its acetate ester
D)a glycoside into a monosaccharide plus an alcohol
E)a monosaccharide plus an alcohol into a glycoside

Question 37

Instructions: Consider the reaction below to answer the following question(s).
Refer to instructions.Q and Z are cyclic examples of:

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

Question 38

Which reagent would be best suited for the transformation shown?

A)alkaline Cu²⁺ in H₂O
B)Ag⁺ in H₂O/NH₃
C)H₂,with Ni catalyst
D)NaNO₃ at 0 ^$\circ$ C
E)NaBH₄ in H₂O

Question 39

Instructions: Consider the reaction below to answer the following question(s).
Refer to instructions.Compound Z is:

A)the D-anomer.
B)the a-anomer.
C)the b-anomer.
D)the L-anomer.

Question 40

Instructions: Draw structures for the products you would expect to obtain from reaction of b-D-galactopyranose with the listed reagents.Be sure to include all relevant stereochemistry.
b-D-galactopyranose
Draw:
Br₂,H₂O

Question 41

Use the information below to answer the following questions.

a) Which of the above represent an aldose?
a. only 1 and 2
b. only 1 and 3
c. only 2 and 3
d. 1, 2 and 3

b) Which of the above would not be oxidized by an aqueous solution of Br2?
a. only 1
b. only 2
c. only 3
d. all of these

Question 42

Which of the following is a disaccharide?

A)glucose
B)fructose
C)sucrose
D)N-acetylgalactosamine
E)both c and d