Digestive

• Nutrients


  • Carbohydrates
  • Proteins
  • Fats
• Nutrient


  Any substance that has a useful function when taken up by the body cells
• Food energy is measured in Joules and Calories (kcal)
• Joule


  1 energy unit
• Calorie


  1 unit of heat, amount of heat required to raise the temperature of 1 gram of water by 1 degree Celsius
• Types of food


  • Organic (produced by a living thing)
  • Inorganic (rocks, soil and sea)
• Organic food types


  • Macronutrients (needed in large amounts) - e.g. fat, protein, carbohydrate
  • Micronutrients (needed in small amounts) - e.g. vitamins, minerals
• Carbohydrates

  • Simple
  • Complex
• Nutrients


  • Proteins
  • Vitamins
  • Minerals
• Proteins


  Made of amino acids
• Vitamins


  • Fat-soluble
  • Water-soluble
• Minerals


  • Include calcium
  • Include iron
• Lipids (Fats)


  • Fatty Acids
  • Glycerol
• Carbohydrates


  • Sugars
  • Starches
• Sample foods


  • Fruits
  • Grains
  • Bread
  • Beans
• Nutrients


  Any substance that has a useful function when taken up by the body cells
• Food energy


  • Measured in calories (kcal) and joules (J)
  • 1 calorie = 4.184 joules
• Food


  • Can be classified as organic (produced by a living thing) or inorganic (rocks, soil and sea)
  • Organic food can be further classified as macronutrients (needed in large amounts) or micronutrients (needed in small amounts)
• Carbohydrates


  Give your body instant energy
• Carbohydrates have the basic structure CH₂OH
• Saliva contains amylase which breaks down carbohydrates into simple sugars.
• Digestion begins with chewing food into smaller pieces to increase surface area for enzymes to work on.
• The digestive system is made up of the mouth, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum, colon, rectum), anus, liver, gallbladder, pancreas.
• The digestion process is the breakdown of food into smaller molecules that can be absorbed by the body.
• Amylase converts starches into disaccharides like maltose.
• Digestion begins with chewing food into smaller pieces to increase surface area for enzymes to act on.
• Simple sugars are absorbed through the walls of the stomach and intestines into the bloodstream where they are transported to all parts of the body.
• Amino acids are the monomers from which proteins are made
• The stomach produces hydrochloric acid that kills bacteria and activates pepsinogen to form pepsin.
• Bile salts emulsify fats so they are broken up into tiny droplets, making it easier for digestive enzymes to break them down.
• Esophagus - muscular tube that carries food from the mouth to the stomach. It has no digestive function but it does push food along using peristalsis.
• Mouth - where food enters through the lips and passes over the teeth and tongue. The salivary glands produce saliva containing amylase that starts breaking down starch into sugar.
• Mechanical digestion involves breaking down food through physical processes such as chewing, grinding, mixing, churning, and peristalsis.
• Chemical digestion involves using enzymes to break down complex substances into simpler ones.
• Enzymes are biological catalysts produced by living organisms that speed up chemical reactions without being used up or changed themselves.
• Maltase converts maltose into glucose.
• Sucrase converts sucrose into glucose and fructose.
• Lipases break down fats into fatty acids and glycerol.
• Lactase converts lactose into glucose and galactose.
• Proteinases break down proteins into peptones and amino acids.