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9: Carbohydrates

Carbohydrate structure, glycosidic bonds, biological roles.

LibreTexts reference: Carbohydrates

D and L Configurations from Fischer Projections

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D-3-keto-altrose⟶L-3-keto-altrose

. . CH2OH
H . . . . OH
. . . .
. ==O 
HO . . . . H
. . . .
H . . . . OH
. . . .
. . CH2OH

Above is a Fischer projection of the monosaccharide D-3-keto-altrose. Which one of the following Fischer projections is of the monosaccharide L-3-keto-altrose?

 

D and L Configurations from Haworth Projections

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α-D-altrose

H . . . CH2OH . . . . . H
. . . .         . . . .
. . / . . . O . .
. . / . H . . . \ . .
/ . . Haworth . . \
. \ . . . . / .
. \ . H . HO . / .
HO . . \ . . . / . . OH
. . . . . . . . .
. . . OH . H . . .

Above is a Haworth projection of the monosaccharide α-D-altrose. Which one of the following Haworth projections is of the monosaccharide α-L-altrose?

 

Common Polysaccharides and Descriptions

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Match each of the following polysaccharides with their corresponding descriptions.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. chitin
Drop Your Choice Here 2. glycogen
Drop Your Choice Here 3. cellulose
Drop Your Choice Here 4. amylose
Drop Your Choice Here 5. amylopectin

Drag one of the choices below:

  • A. polymer of β-linked glucose units found in some animals
  • B. major structural component of cell walls
  • C. linear chain of glucose with α-glycosidic linkages and no branches
  • D. animal polysaccharide that contains α-glycosidic linkages
  • E. highly branched polymer of α-linked glucose units found in plants
 

Characteristics of Common Polysaccharides

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Which one of the following polysaccharides correspond to the description 'linear chain of glucose with α-glycosidic linkages and no branches'.

 

Monosaccharide Classes from Fischer Projections

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Fischer classification problem

. . CH2OH
. ==O 
HO . . . . H
. . . .
. . CH2OH

The diagram above shows a Fischer projection of an unnamed monosaccharide.
Your task is to classify the sugar based on the provided categorizations below. Carefully analyze the structure and check the three categorizations that apply.
Instructions:

  • You are required to select exactly three (3) boxes.
  • Selecting fewer or more than three boxes will be marked as incorrect.
  • No partial credit will be awarded.
 

Monosaccharide Classes from Haworth Projections

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Haworth classification problem

HO . . . CH2OH . . . . . CH2OH
. . . .         . . . .
. . / . . . O . .
. . / . H . . . \ . .
/ . . Haworth . . \
. \ . . . . / .
. \ . H . HO . / .
H . . \ . . . / . . OH
. . . . . . . . .
. . . OH . H . . .

The diagram above shows a Haworth projection of an unnamed monosaccharide.
Your task is to classify the sugar based on the provided categorizations below. Carefully analyze the structure and check the five categorizations that apply.
Instructions:

  • You are required to select exactly five (5) boxes.
  • Selecting fewer or more than five boxes will be marked as incorrect.
  • No partial credit will be awarded.
 

Conversions Between Fischer and Haworth Projections

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α-D-gluco-2-heptulose⟶D-gluco-2-heptulose

H . . . CH2OH . . . . . CH2OH
. . . .         . . . .
. . / . . . O . .
. . / . H . . . \ . .
/ . . Haworth . . \
. \ . . . . / .
. \ . OH . H . / .
HO . . \ . . . / . . OH
. . . . . . . . .
. . . H . HO . . .
Above is a Haworth projection of the monosaccharide α-D-gluco-2-heptulose. Which one of the following Fischer projections is of the monosaccharide D-gluco-2-heptulose?
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