Podcast
Questions and Answers
What is the result of the reaction between the OH group on C5 and the aldehyde carbonyl during cyclization?
What is the result of the reaction between the OH group on C5 and the aldehyde carbonyl during cyclization?
What is the difference between 𝛂-D-glucose and 𝛃-D-glucose?
What is the difference between 𝛂-D-glucose and 𝛃-D-glucose?
What happens during mutarotation in carbohydrates?
What happens during mutarotation in carbohydrates?
What is the product of a dehydration reaction between two monosaccharides?
What is the product of a dehydration reaction between two monosaccharides?
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What is the role of a glycosidic bond in carbohydrates?
What is the role of a glycosidic bond in carbohydrates?
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Which disaccharide is also known as malt sugar?
Which disaccharide is also known as malt sugar?
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In Fischer projections, how are the horizontal bonds represented?
In Fischer projections, how are the horizontal bonds represented?
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How is the configuration about the chiral center most distant from the carbonyl carbon used to differentiate D and L isomers?
How is the configuration about the chiral center most distant from the carbonyl carbon used to differentiate D and L isomers?
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How many chiral centers are present in glucose according to the text?
How many chiral centers are present in glucose according to the text?
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Which statement is true regarding D and L isomers?
Which statement is true regarding D and L isomers?
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What defines D isomers in monosaccharides according to the text?
What defines D isomers in monosaccharides according to the text?
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What term describes sugars that differ only in the configuration around one carbon atom?
What term describes sugars that differ only in the configuration around one carbon atom?
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When converting D-Glucose from Fischer projection to a cyclic monosaccharide, what is the first step?
When converting D-Glucose from Fischer projection to a cyclic monosaccharide, what is the first step?
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In the Haworth projection of glucose, which OH group reacts with the aldehyde carbonyl to form a six-membered ring (pyranose)?
In the Haworth projection of glucose, which OH group reacts with the aldehyde carbonyl to form a six-membered ring (pyranose)?
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What is the key difference between D-Glucose and L-Glucose in terms of chirality centers?
What is the key difference between D-Glucose and L-Glucose in terms of chirality centers?
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Which statement best describes the chirality centers in a Fischer projection of a monosaccharide?
Which statement best describes the chirality centers in a Fischer projection of a monosaccharide?
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For a D monosaccharide, where is the OH group located in relation to the carbonyl group?
For a D monosaccharide, where is the OH group located in relation to the carbonyl group?
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Which type of sugars are glucose and other naturally occurring sugars?
Which type of sugars are glucose and other naturally occurring sugars?
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Study Notes
Stereoisomers of Monosaccharides
- Glyceraldehyde has 2^1 = 2 stereoisomers
- Aldohexoses have 2^4 = 16 stereoisomers due to their four chiral centers
- Steroisomers of monosaccharides can be divided into two groups based on the configuration at the chiral center most distant from the carbonyl carbon
- D-isomers have the same configuration as D-glyceraldehyde, and L-isomers have the same configuration as L-glyceraldehyde
Fischer Projections
- Used to represent compounds with several chirality centers, such as aldohexoses
- The molecule is drawn with a vertical carbon skeleton, with the aldehyde at the top, and horizontal bonds are assumed to come forward (on wedges)
- The CH2OH group at the end of the chain ends up above the carbon skeleton
Cyclization and Anomers
- The OH group on C5 reacts with the aldehyde carbonyl to form a six-membered ring with a new chirality center
- Cyclization yields two isomers, α and β, depending on the location of the OH group on the new chirality center
- The α-isomer (α-D-glucose) has the OH group on the new chirality center drawn down
- The β-isomer (β-D-glucose) has the OH group on the new chirality center drawn up
Mutarotation
- The change in specific rotation that occurs when an α or β form of a carbohydrate is converted to an equilibrium mixture of the two
Disaccharides
- A disaccharide consists of two monosaccharides linked together by a glycosidic bond
- A glycosidic bond is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate, by liberating a water molecule
- Examples of disaccharides include maltose, composed of two D-glucose molecules
Monosaccharides
- Glucose and all other naturally occurring sugars are D-sugars
- L-Glucose, a compound that does not occur in nature, is the enantiomer of D-glucose
- L-Glucose has the opposite configuration at every chirality center
Haworth Structures
- A Haworth projection is a common way of writing a structural formula to represent the cyclic structure of monosaccharides
- The hydroxyl and carbonyl groups can react together to form a ring
- In glucose, the OH group on C5 reacts with the carbonyl carbon to form a six-membered ring (pyranoses)
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Description
Test your knowledge on Fischer projection and monosaccharide stereochemistry concepts. Learn the differences between D and L monosaccharides and how to determine their configurations. Explore the characteristics of D-sugars and the significance of L-glucose in stereochemistry.
