bio-food groups 2

• Food groups


  • Carbohydrates
  • Proteins
  • Fats
  • Vitamins
  • Minerals
  • Fibres
  • Water
• Carbohydrates


  They give energy
• Types of carbohydrates


  • Sugars
  • Starch
• Lack of carbohydrates


  Can give you weakness
• Too much carbohydrates


  Can give you diabetes
• Proteins


  They are used to build materials in the body (muscles, skin..)
• Sources of proteins


  • Meat
  • Pulses
  • Milk
• Lack of protein


  Causes poor growth
• Fats


  They are used to store energy
• Sources of fats


  • Plants (eg sunflowers)
• Too much fatty meat


  Can cause heart diseases
• Nutrients


  • Carbohydrates (energy)
  • Proteins (growth)
  • Vitamins, minerals (healthy)
  • Water (essential)
• Simple carbohydrates


  Made up of sugar molecules (eg glucose, fructose)
• Complex carbohydrates


  Made up of several simple sugar molecules to form long complex chains (eg starch- plants, glycogen- animal)
• Proteins


  Very large molecules made up of small building units known as amino acids
• Proteins cannot be stored in human body
• Uses of proteins


  • Needed for growth and developments
  • Build cells and repair damaged tissues
  • Involved in contraction and relaxation of muscles
  • Destroys or help destruction of foreign bodies such as bacteria (as antibodies)
  • Speed up chemical reaction (as enzymes)
• Benedict's test


  Produces a green/yellow/orange/bricked participate when simple carbohydrate (eg- glucose) is present but it remains blue when absent
• Iodine test


  Carried out to identify starch in food. A blue-black colour shows presence and yellow/brown colour absence of starch
• Biuret test


  Used to test for the presence of protein in food samples. A purple or violet colour is formed in the presence of protein but when protein is absent the colour remains blue
• Emulsion test


  Used to identify presence of fats. White/cloudy colour shows presence and no white emulsion when absent