Categories of carbohydrates and their functions in cells
MONOSACCHARIDES
- Monosaccharides are the simple sugars which are the monomers that make up complex carbohydrates.
- They are composed of a carbon skeleton ranging between 3 to 7 carbons, with an –OH group attached to each C, except for one which is double bonded to an O (Carbonyl-CO)
- Monosaccharides provide a major source of energy for cells (e.g. glucose and fructose). Cells harvest the stored energy in monosaccharides through respiration.
- Types of monosaccharides: Glucose, Fructose & Galactose
DISACCHARIDES
Disaccharides are the combination of 2 monosaccharides joined through glycosidic linkages. Depending on where the –OH group is attached, it’s either an alpha linkage (below the plane of sugars) or a beta linkage (above the plane of sugars). The type of linkage determines the properties of the carbohydrates and decides whether the polymer will be broken down into monomers.
Glucose + Fructose = Sucrose
Glucose + Glucose = Maltose
Glucose + Galactose = Lactose
Disaccharides are the combination of 2 monosaccharides joined through glycosidic linkages. Depending on where the –OH group is attached, it’s either an alpha linkage (below the plane of sugars) or a beta linkage (above the plane of sugars). The type of linkage determines the properties of the carbohydrates and decides whether the polymer will be broken down into monomers.
Glucose + Fructose = Sucrose
Glucose + Glucose = Maltose
Glucose + Galactose = Lactose
POLYSACCHARIDES
Polysaccharides are long chains of carbohydrates with several thousands of monomers. Oligosaccharides are shorter chains of carbohydrates with about 5 to 20 sugar molecules)
Storage polysaccharides= used for energy utilization
Starch: (α-1,4 linked glucose)/ major storage products in potato, rice, wheat and corn.
Glycogen: (α-1,4), highly branched/ stored in the liver and muscles of animals
Structural polysaccharides: used to build cell walls and exoskeletons
Cellulose: (β-1,4 linked glucose), major component of plant cell walls
Callose: (β-1,3 linked glucose), shorter than cellulose and formed in wounding sites in plants
Chitin: (β-1,4 linked N-acetyl glucosamine), major structural component of exoskeletons of insects and cell walls of fungi
Polysaccharides are long chains of carbohydrates with several thousands of monomers. Oligosaccharides are shorter chains of carbohydrates with about 5 to 20 sugar molecules)
Storage polysaccharides= used for energy utilization
Starch: (α-1,4 linked glucose)/ major storage products in potato, rice, wheat and corn.
Glycogen: (α-1,4), highly branched/ stored in the liver and muscles of animals
Structural polysaccharides: used to build cell walls and exoskeletons
Cellulose: (β-1,4 linked glucose), major component of plant cell walls
Callose: (β-1,3 linked glucose), shorter than cellulose and formed in wounding sites in plants
Chitin: (β-1,4 linked N-acetyl glucosamine), major structural component of exoskeletons of insects and cell walls of fungi