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

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

4. 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

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

6. Photosynthesis

9. carbon dioxide + water glucose + oxygen
light
chlorophyll
CO H2O C6H12O O2

10. Types of carbohydrate
Sugars
glucose
fructose
maltose
sucrose
Starches

11. Testing for carbohydrates

12. Testing for sugars

13. Testing for starch

14. 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

15. Structure of carbohydratesHO
H2O
+ water HO OH O

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

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

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

20. Hydrolysis of starch
Mixture of glucose and starch solution
water

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