Summarizing Carbohydrates

Summary of lessons so far

Carbohydrates are a group of macromolecules that are a vital energy source for the cell and provide structural support to plant cells, fungi, and all of the arthropods that include lobsters, crabs, shrimp, insects, and spiders.

Carbohydrates are classified as monosaccharides, disaccharides, and polysaccharides depending on the number of monomers in the molecule. Monosaccharides are linked by glycosidic bonds that are formed as a result of dehydration reactions, forming disaccharides and polysaccharides with the elimination of a water molecule for each bond formed.

Glucose, galactose, and fructose are common monosaccharides, whereas common disaccharides include lactose, maltose, and sucrose. Starch and glycogen, examples of polysaccharides, are the storage forms of glucose in plants and animals, respectively. The long polysaccharide chains may be branched or unbranched.

Cellulose is an example of an unbranched polysaccharide, whereas amylopectin, a constituent of starch, is a highly branched molecule. Storage of glucose, in the form of polymers like starch of glycogen, makes it slightly less accessible for metabolism; however, this prevents it from leaking out of the cell or creating a high osmotic pressure that could cause excessive water uptake by the cell.

Glossary of Words


biological macromolecule in which the ratio of carbon to hydrogen and to oxygen is 1:2:1; carbohydrates serve as energy sources and structural support in cells and form the cellular exoskeleton of arthropods


polysaccharide that makes up the cell wall of plants; provides structural support to the cell


type of carbohydrate that forms the outer skeleton of all arthropods that include crustaceans and insects; it also forms the cell walls of fungi


two sugar monomers that linked together by a glycosidic bond


storage carbohydrate in animals

Glycosidic bond

bond formed by a dehydration reaction between two monosaccharides with the elimination of a water molecule


single unit or monomer of carbohydrates


long chain of monosaccharides


stored carbohydrate in plants

[Attributions and Licenses]

This is a lesson from the tutorial, Biological Macromolecules and you are encouraged to log in or register, so that you can track your progress.

Log In

Share Thoughts