1. Carbohydrates Objectives: Ability to define the term biological chemicals Understand the structure & classification of carbohydrates Knowledge of the functions of carbohydrates within the body

2. Biological Chemicals The chemical basis of living things Carbohydrates Lipids Proteins Water Nucleic acids Enzymes

3. Carbohydrates What are they? Sugars & starches What are they made up from? Carbon, hydrogen & oxygen What proportions of each? 1: 2 : 1

4. Monosaccharides Simplest of carbohydrates Sweet-tasting Dissolves in water Straight chain or ring structure Example: Glucose

5. Structure of Monosaccharides Glucose – formula C(6)H(12)O(6) Can be represented by a STRAIGHT CHAIN Or as a 6-sided structure called a PYRANOSE RING Most molecules exist as rings rather than single chains

6. Disaccharides Double-sugar Sweet, soluble & crystalline 2 monosaccarides combine together This is called a glycosidic bond Examples: Maltose = glucose + glucose Sucrose = glucose + fructose Lactose = glucose + galactose

7. Polysaccharides Many monosaccarides join together Chains may be folded & compact Ideal for storage Examples: starch & glycogen However, not all used for storage Example: cellulose – strengthens & supports cell walls

8. Functions of carbohydrates Principally a respiratory substrate i.e. oxidized to release energy Cell division Muscle contraction

9. Sources of carbohydrates Starch, sugars & cellulose are the main carbohydrates we eat Reserves stored as glycogen in liver & skeletal muscles About 50% of the average diet More active = higher percentage Examples: Rice, potatoes, wheat, cereal grain