biology

• Nutrition


  Essential process by which living organisms obtain food containing nutrients
• Nutrients


  Chemical compounds found in foods that provide nourishment for the body
• Food Nutrients


  • Carbohydrates
  • Proteins
  • Lipids (Fats & Oils)
• Carbohydrates


  Made up of carbon, hydrogen and oxygen
• Carbohydrates


  • Include starch, cellulose (found in plant cell wall) and sugars
  • Simplest form is glucose, a sugar found in honey and dried fruits
• Glucose


  A sugar that can provide energy for the body
• Types of Carbohydrates


  • Simple
  • Complex
• Simple Carbohydrates


  • Generally taste sweet
  • Easier to digest, spike blood glucose level quickly
  • Suitable for short energy outbursts
• Complex Carbohydrates


  • Not typically sweet
  • Take longer to digest, provide consistent energy
  • Include starch and fibers
• Monosaccharide


  Sugars with one ring of atoms, e.g. glucose and fructose
• Disaccharide


  Sugars with two rings of atoms, e.g. maltose
• Polysaccharide


  Sugars with long chains of repeating units, e.g. starch
• Iodine Test for Starch

  1. Grind food into fine pieces

  2. Add iodine solution

  3. Observe colour change
• Benedict's Test for Reducing Sugars

  1. Heat water

  2. Grind food into fine pieces

  3. Add food sample and Benedict's solution

  4. Heat in water bath

  5. Observe colour change
• Amino acids


  The simplest form of proteins, made up of carbon, hydrogen, oxygen and nitrogen
• Amino acid structure


  Amino group, R group, Carboxyl group
• Functions of Proteins


  • Building and repairing tissues
  • Hormone production
  • Muscle contraction and movement
  • Transport of oxygen (hemoglobin)
  • Blood clotting
  • Enzymes
  • Providing strength and structure
• Biuret Test for Proteins

  1. Grind food into fine pieces

  2. Add food sample, hydroxide solution, copper sulphate solution

  3. Observe colour change
• Fats and oils are examples of Lipids
• Lipids are insoluble in water and soluble in alcohol
• Lipids provide energy for the body
• It is not okay to eat foods with high lipid content everyday
• Lipid molecules are made up of carbon, hydrogen and oxygen
• Putting lipids on paper leaves a grease mark
• Cheese, butter, chicken skins, steak and mayonnaise are not considered 'healthy fats'
• Cholesterol is a type of lipid found in animal products
• Lipids are an important component of having a balanced diet
• Omega 3 and Omega 6 are examples of fatty acids
• Lipids


  Fats are solid at room temperature, oils are liquid at room temperature, made up of carbon, hydrogen and oxygen
• Lipid structure


  1 molecule of glycerol, 3 fatty acids
• Functions of Lipids


  • Energy storage
  • Insulation and protection
  • Hormone production
  • Vitamin absorption
• Classification of Fatty Acids

  • Saturated (no double bonds)
  • Monounsaturated (one double bond)
  • Polyunsaturated (more than one double bond)
• Saturated Fats


  • Contribute to bad cholesterol, found in animal products
• Monounsaturated Fats


  • Healthy fats found in peanuts, olives, avocados, salmon
• Polyunsaturated Fats


  • Healthy fats, include Omega-3 (found in fatty fish, flaxseeds, walnuts) and Omega-6 (found in vegetable oils, nuts, seeds)
• Grease Spot Test for Lipids


  1. Grind food into fine pieces

  2. Place on paper, let dry

  3. Observe transparent spot
• Emulsion Test for Lipids


  1. Grind food into fine pieces

  2. Add food sample, ethanol, water

  3. Swirl and observe cloudy white emulsion