• Photosynthesis • Elemental composition and classification of carbohydrates • Properties of sugar, starch and non-starch polysaccharides • Effects of heat on carbohydrates
• Biological functions, Recommended Daily Allowance (RDA)/Reference Intake (RI) and energy value of carbohydrates
• Associated dietary disorders • Digestion, absorption and utilisation of carbohydrates
Carbohydrates are one of the macronutrients. They provide an essential source of energy. They are mainly found in plants, where they are manufactured by photosynthesis.
Photosynthesis hyl
Photosynthesis is the process by which green plants use sunlight to make sugar (glucose) from carbon dioxide and water.
How photosynthesis occurs • Plant roots absorb water (H2
(CO )2
• Leaves take in carbon dioxide (CO2 the air.
• Chlorophyll (green pigment) in leaves absorbs energy from the sun.
Result • Glucose (sugar) (C6
• Oxygen (O2 H12 O6 ) is formed. ) is released into the air.
Equation for photosynthesis 6H2
6CO2 Carbon dioxide + O Water
Light energy Chlorophyll
C6H12 O6 Glucose + 6O2 Oxygen
Elemental composition of carbohydrates Carbohydrates are made up of three elements: carbon (C), hydrogen (H) and oxygen (O).
? List the three elements found in carbohydrates. (3) OL Leaving Certificate Home Economics 17
