Digestion

• Digestive System/gut/elementary canal


  1. chemical -digestion/enzymes

  2. physical chewing / teeth

  3. seperation-emulsification /bile

  4. Llarge fat drops->small fat droplets
• Food Tests
• Qualitative


  no numbers
• Positive test result


  involves a colour change
• Negative test result


  means no colour change
• The food substance is a Liquid
• food substance not present
• Biological catalyst
• two classes


  • metabolic, all reactions in cells
  • digestive, gut
• Digestive chemical breakdown of food molecules
• large digestion


  1. →>small/Soluble st molecules

  2. enzymes

  3. molecules
• food molecules (substrates)
• a protein molecule is made up of

  many different amino acids
• a fat molecule is made up of


  fatty acid and glycerol molecules
• a starch molecule is made up of

  many glucose molecules
• Enzyme action


  Enzyme action
• Effect of temperature on the rate of an enzyme controlled reaction

  • the reaction works as fast as possible
  • the rate of the reaction increases with the increase in temprature
  • Steady increase
  • Rapid decrease- the enzyme is denatured and stops working
• Digestion processes
• digestion


  the process of chemical breakdown of food molecules
• emulsification

  the breakdown of large fat drops to small fat droplets
• absorption


  the process of moving digested molecules from the system & blood stream
• assimilation


  the use of the molecules / incorporation
• egestion


  you remove undigestable waste
• excretion


  the removal of products that have been used in the metabolism
• amino acids


  the breakdown products of proteins
• fatty acids

  the products of fatty acids
• Component of the diet

  • Protein
  • Carbohydrates
  • Fat
  • Vitamin A
  • Vitamin B
  • Vitamin C
  • Vitamin D
  • Calcium
  • Iron
  • Fibre
  • Water
• Protein


  For growth and repair
• Carbohydrates


  Needed to release energy in our cells
• Fat


  Insulation to maintain body temperature
• Vitamin A


  Helps cells to grow and keeps skin healthy. Helps eyes to see in poor light
• Vitamin B


  For healthy skin and to keep the nervous system working properly
• Vitamin C


  For healthy skin, teeth and gums
• Vitamin D


  For strong bones and teeth
• Calcium


  Needed for strong teeth and bones. Involved in the clotting of blood
• Iron


  Needed to make haemoglobin in red blood cells
• Fibre

  Adds bulk to food so it can be easily moved clong the digestive system by peristalsis. Fibre is thought to help prevent bowel cancer
• Water


  Necessary for all life processes
• Enzymes are biological catalysts. This means they speed up reactions, often by over a million times, without being used up themselves
• Enzymes are made of proteins. Each protein molecule is made of a long chain of amino acids, folded up into a complex shape