18 Questions
Which type of isomers differ due to the H and OH configuration of carbons 2, 3, or 4?
Epimers
What type of isomers have the same structural formula but different spatial configurations?
Enantiomers
In stereochemistry, what is added after cyclisation, leading to the alpha- and beta-configurations of a sugar?
Anomers
Which type of carbohydrate is not an epimer nor an enantiomer?
D-Galactose and D-mannose
How many asymmetric carbons do the D and L configurations of glyceraldehyde contain?
One
What type of isomers have the C-1 in a ring structure as the asymmetric center, resulting in alpha- and beta-configurations?
Anomers
What is the term for every individual monomeric unit of a carbohydrate?
Monosaccharide
Which of the following is an example of a 5-carbon monosaccharide?
Ribose
What is the main difference between ketoses and aldoses?
Spatial arrangement
Which type of isomers have no variation in spatial arrangement?
Structural isomers
Which pair represents a 5-carbon monosaccharide and its structural isomer?
(Ribose, Ribulose)
How many aldoses and ketoses can be identified among 8 hexose sugars?
(8 aldoses, 4 ketoses)
What type of group do carbohydrates contain in their structures?
Aldehyde (-CHO) or ketone (-C=O) group
What is the general classification of carbohydrates based on the number of monomeric units present?
Monosaccharides, Disaccharides, Oligosaccharides, Polysaccharides
Which type of carbohydrate contains an aldehyde or ketone group?
Monosaccharides
What distinguishes simple carbohydrates from complex carbohydrates?
Simple carbohydrates consist of one or two sugar units, while complex carbohydrates consist of multiple sugar units.
Which of the following is NOT a classification of carbohydrates?
Triacylglycerols
In which classification do we find carbohydrates with two monomeric units present?
Disaccharides
Study Notes
Monosaccharides and Stereoisomers
- Monosaccharides, except dihydroxyacetone, contain 1 or more asymmetric carbons.
- D- and L- configurations of glyceraldehyde have a single asymmetric carbon and are mirror images.
- Epimers are isomers that differ due to the H and OH configuration of carbons 2, 3, or 4.
- Examples of epimers: D-glucose and D-mannose at C-2, and D-glucose and D-galactose at C-4.
- D-glucose and D-galactose are not epimers, but diastereoisomers, since they differ at more than 1 carbon.
Anomers
- Anomers are formed when a ring structure is created, resulting in an additional asymmetric carbon.
- The C-1 in a ring structure can become the asymmetric centre of the ring, resulting in alpha- and beta-configurations of the sugar.
Stereoisomers
- Stereoisomers have the same structural formula but with different spatial configurations.
- Optical activity is influenced by the presence of asymmetric carbons or chirality.
Monosaccharides Classification
- Monosaccharides can be classified into several classes based on the number of carbon atoms present:
- Trioses: 3-carbon monosaccharides
- Tetroses: 4-carbon monosaccharides
- Pentoses: 5-carbon monosaccharides
- Hexoses: 6-carbon monosaccharides
- Heptoses: 7-carbon monosaccharides
Structural Isomerism
- Ketoses are isomers of aldoses, with the same number and kinds of atoms, but different structural or spatial configurations.
- Examples of structural isomers:
- Erythrose (Aldose) and Erythulose (Ketose): 4-carbon monosaccharide
- Ribose and Ribulose: 5-carbon monosaccharide
- Xylose and Xylulose: 5-carbon monosaccharides
Carbohydrates Introduction
- Carbohydrates are essential components of all living organisms.
- Carbohydrates contain an aldehyde (-CHO) or ketone (-C=O) group with two or more hydroxyl (-OH) groups in their structures.
- Examples of carbohydrates: Glyceraldehyde, Dihydroxyacetone, Glucose, Fructose.
Test your knowledge on carbohydrates and monosaccharides with this quiz. Learn about the different types of monosaccharides such as glucose, fructose, and ribose, and understand their structures and properties.
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