Chapter 3Food. Why do we need Food? 1.Source of Energy 2.To make chemicals needed for metabolic reactions 3.As the raw materials for growth and repair.

Chapter 3 Food

Why do we need Food?1. Source of Energy2. To make chemicals needed for metabolic reactions3. As the raw materials for growth and repair of

structures in an organism.

Elements Present in FoodMainly made up of 14 elementsThe six common elements found in food are:

Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P) and Sulphur (S)

Compounds containing Carbon are known as organic compounds.

There are 5 elements present as dissolved salts are: Sodium (Na), Magnesium (Mg), Chloride (Cl), Potassium (K) and Calcium (Ca).There are 3 trace (tiny quantities) elements:Iron (Fe), Copper (Cu), Zinc (Zn).

Biomolecules contain carbon and are also called biochemicals.

There are 4 main groups of biomolecules:CarbohydratesLipids (fats, oils)ProteinsVitamins

CarbohydratesElements in Carbohydrates: Carbon (C), Hydrogen (H), Oxygen (O)

Elements are usually present in the ratio:

Where X and Y are the same number (i.e. X = Y)

Formula for Glucose:

Glucose is made by plants in photosynthesis and it is the main molecule used by living things for energy.Fructose: Same formula as glucose buy atoms arranged in a different way. Found in fruits and sweeter than glucose.

4. Vitamins

Vitamins are complex carbon based substances that the body cannot make.

Two types:

a) Water Soluble Vitamins

b.

Minerals