Carbohydrates

Carbohydrates Small sugar molecules to large sugar molecules. Carbo = carbon, hydrate = water Examples: A. monosaccharide B. disaccharide C. polysaccharide

Carbohydrates: Monosaccharide: the monomer of carbohydrates one sugar unit Examples: glucose (C6H12O6) deoxyribose ribose Fructose Galactose glucose

Carbohydrates: Glucose = blood sugar All cells use glucose for energy

Carbohydrates: Monosaccharides An OH (hydroxyl) group is attached to each carbon except one, which is double bonded to an oxygen (carbonyl).

Carbohydrates: Classified according to the size of their carbon chains, varies from 3 to 7 carbons. Triose = 3 carbons Pentose = 5 carbons Hexose = 6 carbons

Carbohydrates:

Carbohydrates: Disaccharide: a two-sugar unit Made by joining together two monomers and removing a water molecule. What is the name of this process? Examples: Sucrose (glucose+fructose) – table sugar Lactose (glucose+galactose) – milk sugar Maltose (glucose+glucose) – seed sugar

Examples of Disaccharides: Carbohydrates: Examples of Disaccharides: Oligosaccharides (“oligo-” means few or scant). Several monosaccharides joined together. Sucrose (table sugar) is disaccharide of one glucose and one fructose (Fig 3-1, p39). Often combined with other molecules. Many larger molecules have oligosaccharides attached for various purposes. Sometimes used for cell ID. The cell membrane has many proteins in it, some of which have attached oligosaccharides projecting away from the cell. Sometimes these are used as chemical labels for cell type.

Examples of Disaccharides: Lactose = glucose + galactose Sucrose = glucose + fructose

Carbohydrates Polysaccharide: many sugar units. Structure: Polymers of a few hundred or a few thousand monosaccharides. Examples: starch (bread, potatoes) glycogen (beef muscle) cellulose (lettuce, corn) glucose cellulose

Chitin

Carbohydrates: Functions Store energy in chemical bonds Starch is a storage form of energy found in plants. Glycogen is a highly branched chain used by animals to store energy in muscles and the liver.

Carbohydrates: Functions Structural component Chitin is a polysaccharide used as a structural material in arthropod exoskeleton and fungal cell walls. Cellulose is a fiber-like structural material - tough and insoluble - used in plant cell walls Cell-cell communication