2 Discussion Questions: (Groups of 2 – 5 minutes!!!) List some food items rich in carbohydrates.What is the difference between complex carbohydrates versus simple carbohydrates?Would you recommend a person who wants to lose weight to adopt a low-carb diet?
3 Canada’s Food GuideCarbohydrates make up the largest volume of our daily foodCarbohydrates are found in: grain flour, cereals, pasta, potatoes and other vegetables, fruits, syrups, honey, candy, pop, juice, milk as well as in the pure crystalline form of our familiar table "sugar".
4 Functions of Carbohydrates Energy sourcePlays a vital part in the digestion, metabolism, and oxidation of protein and fat.Too much carbohydrate =Glycogen in liver ORFat
5 Simple versus Complex Carbohydrates Simple Carbs:Quick source of energy (do not supply other nutrients or fiber)Quickly absorbed – rapid increase in blood sugar level followed by quick declineSmall molecules (glucose, fructose, maltose, sucrose, lactose)Found in: fruit, fruit juice, table sugar, honey, soft drinks, and other sweetsComplex Carbs:Supply energy and other nutrients and fiberSlowly digested – steady slow rise in blood sugar levelLarge molecules (starch and dietary fiber)Starch: breaks down into smaller carbs; supplies long, sustained energy to the bodybread, cereal, potatoes, pasta, rice, and legumes (dried peas and beans)Dietary fiber:found in plant cells (non-digestible part of plants)tough and stringyit does not break down completely in the bodyEssential for regulating the body (digestion).bran, whole-grain foods, raw vegetables and fruit (especially the seeds and skins), legumes, nuts, seeds and popcorn
6 Some General Chemical Info Hydrophilic organic moleculeGeneral formula(CH2O)n , n = number of carbon atomsfor glucose, n = 6, so formula is C6H12O6Names of carbohydratesword root sacchar- or the suffix -ose often usedmonosaccharide or glucose
7 Aldoses and Ketoses Aldoses contain the aldehyde group Ketoses contain the ketone group
8 Ring FormationIn aqueous solution, the aldehyde and ketone groups react with hydroxyl (-OH) group belonging to the same molecule
9 Monosaccharides Simplest carbohydrates General formula is C6H12O6 structural isomersThree major monosaccharidesglucose, galactose and fructosemainly produced by digestion of complex carbohydrates
10 Sugar DerivativesThe hydroxyl groups of a simple monosaccharide can be replaced by other groups
11 Alpha (a) and Beta (b) Links The hydroxyl group on the carbon that carries the aldehyde or ketone can rapidly change from one position to the otherba
12 Disaccharides Pairs of monosaccharides Three major disaccharides sucroseglucose + fructoselactoseglucose + galactosemaltoseglucose + glucose
13 Dehydration Synthesis of a Disaccharide Dehydration synthesis of two glucose molecules results in the formation of maltoseThe C-O-C bond formed is called a glycosidic bond
14 Polysaccharides Starch, cellulose and glycogen long chains of glucose form these polysaccharidesStarch produced by plants is digested by amylaseCellulose gives structure to plants, fiber to our diet
15 Starch HydrolysisThe digestion of starch occurs by the hydrolysis of the glycosidic bond.Amylase is the enzyme.Maltose is the product.
16 PolysaccharidesGlycogen is an energy storage polysaccharide produced by animalsLiver cells synthesize glycogen after a meal to maintain blood glucose levels
17 Carbohydrate Functions Source of energyConjugated carbohydratesglycolipidsexternal surface of cell membraneglycoproteinsmucus of respiratory and digestive tractsproteoglycanscarbohydrate component dominantcell adhesion, gelatinous filler of tissues (eye) and lubricates joints
18 Moieties of Macromolecules A moiety is a chemically different component of a conjugated macromoleculeGlycolipidglycoprotein