An Introduction to Carbohydrates Chapter 5 An Introduction to Carbohydrates

Key Concepts Sugars and other carbohydrates are highly variable in structure. Monosaccharides are monomers that polymerize via condensation reactions to form polymers called polysaccharides. The monosaccharides in polysaccharides are joined by different types of glycosidic linkages. Carbohydrates have diverse functions in cells. In addition to serving as new material synthesizing other molecules, they provide fibrous structural materials, indicate cell identity, and store chemical energy.

Carbohydrate Structure Location of the carbonyl Carbon and oxygen double bonded Number of carbons triose - 3; pentose - 5; hexose - 6 Spatial orientation of hydroxyl groups Carbon bonded with an -OH

Formation of Carbohydrates Monomer of a carbohydrate (polysaccharide) Sugar (ex. glucose, fructose) Monosaccharide Condensation Reaction linkage of two monomers to form a covalent bond with the release of water combination of two hydroxyl groups forms a glycosidic linkage

Types of Carbohydrates in Cells Starch - Energy storage in plants Glycogen - Energy storage in animal cells Chitin - Used for structural support in the cell walls of fungi and the external skeletons of insects and crustaceans. Peptidoglycan - Used for structural support in bacterial cell walls

Functions in Cells, cont’d Structural (see previous slide) Cell identity - glycoproteins distinguish your body cells with foreign cells Store chemical energy - photosynthesis converts sun energy into chemical energy in the form of glucose