Biological molecules

• • Carbohydrates are made up of simple sugars
  • They contain the elements hydrogen carbon and oxygen
  • Starch and glycogen are large, complex carbohydrates.
  • Maltose and glucose are small units that make up these
• • proteins are made up of amino acids
  • They all contain carbon, nitrogen, hydrogen and oxygen atoms
• • Lipids are made up of fatty acids and glycerol
  • Lipids (fats and oils) are built from fatty acids and glycerol
  • Lipids contain carbon, hydrogen and oxygen atoms.
• To take a food sample

  • Get a piece of food and break it up using a pestle and mortar
  • Transfer the ground up food to a beaker and add some distilled water
  • Give the mixture a good stir with a glass rod to dissolve some of the food
  • Filter the solution using a funnel lined with filter paper to get rid of the solid bits of food
• Benedicts to test for glucose

  Prepare a water bath

  Add some benedicts solution to the test tube

  If it contains glucose, the solution will go from blue to brick red

  If not stays blue

  Blue ---> Green ----> Yellow -----> Brick red
• Iodine solution to test for starch

  Goes from browny orange to bluey black
• Biuret test to test for proteins

  Goes from blue to purple
• Sudan III test to test for lipids

  Seperates into two layer, top layer being bright red.
• Carbohydrates: Found in past rice and sugar

  • Provides energy
• Lipids: Found in butter, oily fish

  • Provides energy, act as energy stores and provides insulation.
• Proteins: Found in meat and fish

  • Needed for growth and repair of tissues
• Vitamins:

  • A: Found in live, helps to improve vision and keep your skin and hair healthy.
  • C: Found in fruit, needed to prevent scurvy
  • D: Eggs, needed for calcium absorption
• Mineral ions

  • Calcium: Found in milk and cheese, needed to make bones and teeth
  • Iron: Red meat, needed to make haemoglobin for healthy blood
• Water: Found in cucumber

  • Every bodily function needs water
• Dietary fibre: Found in wholemeal bread and fruit

  • Aids the movement of food through the gut
• Active people need more energy than people who don't do regular excersise
• Children and teenagers need more energy than older people - they need energy to grow and they're generally more active
• Pregnant women need more energy than other women- they've got to provide the energy their babies need to develop