Topic 3.1/2

• Dietary recommendations

  • Recommended amounts of nutrient intake
  • 55–75 % carbohydrate
  • 10−30 % fat
  • 10−15 % protein (based on age)
  • Reduce daily sodium intake
  • Keep trans fatty acid consumption as low as possible
  • Reduce the intake of calories from solid fats and added sugars
  • Choose a variety of protein foods (seafood and beans)
  • Adequate water consumption
• Carbohydrates

  1760 kJ
• Lipids

  4000 kJ
• Protein

  1720 kJ
• Macronutrients

  • Lipids (fat)
  • Carbohydrates
  • Water
  • Protein
• Micronutrients

  • Vitamins
  • Minerals
• Macronutrients

  • Provide the energy necessary to maintain bodily functions during rest and physical activity (needed in large amounts)
• Micronutrients

  • Facilitate energy release and tissue synthesis (needed in small amounts)
• Carbohydrates

  • Metabolic fuel for the body and act as energy storage
  • Synthesis of DNA and RNA
  • Glucose is oxidised back into the ______
• Simple carbohydrates

  • Taste sweet because of chemical arrangement
  • Monosaccharides and disaccharides
  • Monosaccharides are 1 chemical composition
  • Disaccharides such as sucrose and lactose
  • Give us quick burst of energy however runs out quickly
• Complex carbohydrates

  • Supply longer lasting energy
  • Oligosaccharides and polysaccharides
  • Oligosaccharides are 3-9 molecules and longer than 10 is polysaccharides
  • Low GI (glycaemic index) better for you because they digest slower
• Protein

  used for muscle tissue / structures in the body ✔

  components/amino acids are used for making enzymes ✔
• Lipids

  Protect vital organs and help with thermoregulation
• Water

  Transportation and thermoregulation
• Fibre

  Helps the digestive system
• Vitamins

  Energy release from macronutrients
• Minerals

  Elements found in food that are used by the body
• The chemical composition of a glucose molecule is CH₂O with a ratio of 1:2:1, which equals C₆H₁₂O₆
• Condensation Reaction

  1. Combination of two or more monosaccharides to create a disaccharide or a polysaccharide where a water molecule is removed

  2. Monosaccharides can undergo a series of condensation reactions, adding one unit after another to the chain until a polysaccharide is formed

  3. When two monosaccharides react, a water molecule is lost and a disaccharide is created

  4. When one glucose molecule combines with another glucose molecule it creates maltose which is a disaccharide

  5. When a lot of glucose molecules combine together, they create a polysaccharide, for example, glycogen
• Proteins

  • Functional groups
  • Structural groups (muscles, bones, skin, cells)
  • Transport
• The chemical composition of a protein molecule is a ratio of 1:1:1:1 - 1 Carbon : 1 Hydrogen : 1 Oxygen : 1 Nitrogen
• Essential amino acids

  cannot be synthesized by the human body and must be obtained from diet ✔

  meat / fish / processed soybean / bread / protein bars ✔
• Non-essential amino acids

  Can be made by the body
• The composition of a molecule of triacylglycerol is 1 Glycerol : 3 Fatty Acids
• Saturated fatty acids

  Have no double bonds between their carbon atoms, solid at room temperature, from animal sources (e.g. butter)
• Unsaturated fatty acids

  Have one or more double bonds between their carbon atoms, liquid at room temperature, from plant-based foods (e.g. oil)
• Metabolism


  All the biochemical reactions that occur within an organism, including anabolic and catabolic reactions
• Anabolism


  Energy requiring reactions whereby small molecules are built up into larger ones
• Aerobic catabolism


  Aerobic pathway: When oxygen is available pyruvate enters the mitochondria where it is oxidised to carbon dioxide and water
• Anaerobic catabolism


  The breakdown of complex chemical substances into simpler compounds, with the release of energy, in the absence of oxygen
• Glycogen


  Stored glucose, it is a polysaccharide made out of glucose
• Glycogen


  • Stored in the liver and muscles
• Triglyceride storage


  • Stored in adipose tissue (fat) and in skeletal muscle
• Role of insulin


  1. Transforms glucose to glycogen and stores it in the liver and in muscles

  2. Transforms glycerol and fatty acids to lipids, and amino acids into proteins, and stores this in the body

  3. Stops glycogenolysis, lipolysis and the breakdown of proteins into amino acids

  4. Helps to maintain a normal level of sugar in the blood
• Glycogenolysis


  The breakdown of glycogen back into glucose so it can be released into the blood due to low glucose levels
• Lipolysis


  process of releasing triglycerides from the body fat stores into the bloodstream due to decreased glucose levels and absence of glycogen
• Role of glucagon and adrenaline during fasting

  1. Levels of glucagon and adrenaline increase

  2. Glucagon causes glycogenolysis (glycogen into glucose)

  3. Adrenaline stimulates glycogenolysis, causing an increase in blood sugar levels

  4. Both hormones are lipolysis inducers, they mobilize fat stores from the adipose tissues for breakdown into useful energy
• Role of insulin and muscle contraction on glucose uptake during exercise

  1. Insulin stimulates glucose uptake from the blood into skeletal muscle

  2. During exercise, insulin levels fall, and glucagon and adrenaline levels rise, so less glucose is absorbed by the liver and more glycogenolysis occurs causing the release of more glucose into the blood

  3. during periods of no exercise, insulins causes glucose uptake
• Aerobic pathway: When oxygen is available pyruvate enters the mitochondria where it is oxidised to carbon dioxide and water


  Aerobic pathway
• Anaerobic pathways: Without oxygen, pyruvate cannot enter the aerobic pathway, instead it undergoes fermentation or lactic acid production.