Natural products: carbohydrates Intermediate 2 Chemistry Unit 2(e)

Key questions What are carbohydrates? Why are they important to life?

Carbohydrates Compounds which contain carbon, hydrogen and oxygen, the hydrogen:oxygen ratio being 2:1 C6H12O6 C12H22O11 They are made by plants They supply they body with energy

Overview There are three basic types of foodstuff: Fats and oils Proteins Carbohydrates

Photosynthesis

carbon dioxide + water glucose + oxygen light chlorophyll CO2 + H2O C6H12O6 + O2

Types of carbohydrate Sugars glucose fructose maltose sucrose Starches

Testing for carbohydrates

Testing for sugars

Testing for starch

Respiration The process by which the body obtains a supply of energy by breaking down carbohydrates (using oxygen) to give carbon dioxide and water. glucose + oxygen carbon dioxide + water

Structure of carbohydrates HO H2O + water HO OH O

Sugars are small molecules e.g. glucose Starch is a condensation polymer of glucose Plants convert glucose into starch to store energy

Digestion The opposite process happens during digestion + H2O HO O OH

This is a hydrolysis reaction The glucose is carried by blood to body cells Starch can be hydrolysed by acid and by enzymes

Hydrolysis of starch Mixture of glucose and starch solution water

Enzymes Biological catalysts Function best at body temperature They are destroyed (denatured) at higher temperatures