Digestive System and enzymes

  • Created by: Abc312
  • Created on: 08-05-18 20:33
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  • Human Digestive System and Enzymes
    • The digestive system is an organ system.
      • They work together to absorb and digest food.
    • Enzymes can be simply shown with a lock and key theory
      • The induced fit model is how enzymes actually work as  when the substrate attaches the active site binds to in=t for a tighter fit.
    • The three enzymes are
      • Lipase
        • Breaks down lipids(fats and oils)
          • Into glycerol and fatty acids
        • It is made in:
          • The pancreas
          • The small intestine
        • Active in:
          • Small intestine
      • Protease
        • Breaks down proteins
          • Into Amnio acids
        • It is made in:
          • The stomach (pepsin)
          • The pancreas
          • The small intestine
        • Active in:
          • Stomach
          • Small intestine
      • Amylase (a type of carbohydrase)
        • Breaks down starch
          • Into Maltose and other sugars.
        • It is made in:
          • The salivary glands
          • The pancreas
          • The small intestine
        • Active in:
          • The mouth
          • The small intestine
    • Enzymes speed up the rate of chemical reactions.
      • They remain unchanged after the reaction.
    • Enzymes are large proteins made up of chains of amino acids.
    • Each enzyme has a specific active site where the substrate fits into.
    • Every enzyme works best at a specific temperature and pH.
      • A higher temperature increases the rate of reaction at first but if it is too high the active site denatures and the substrate won't fit anymore.
      • Most enzymes work best at pH 7 but pepsin works best at pH 2 in the stomach.
    • Investigating EnzymaticReactions
      • You can look at how pH affects enzyme rate of reactions.
        • You need to use the same temperature water for each test.
          • Put a drop of iodine into every spot in a spotting tile.
            • Add 1cm3 of amylase solution and then 1cm3 of buffer solution of certain pH.
              • Put the test tube in the water  for 5 minutes so it gets to the correct temperature.
                • Add 5cm3 of starch solutions the tube and start a stopwatch.
                  • Every 30 seconds take a sample with a pipette and place in a spot in the tile.
                    • When the iodine doesn't turn black it means starch is no longer present so then  record the time.
                      • Repeat with different pH values.
    • Digestive enzymes break down food into smaller soluble molecules that can be absorbed into the bloodstream.
    • The body uses the products of digestion to make new carbohydrates, proteins and lipids some of the glucose is used in respiration.
    • Bile
      • Bile is produced in the liver
      • It is stored in the all bladder
      • It works in the small intestine
      • The hydrochloric acid in the stomach makes it too acidic for the enzymes in the small intestine to work.
        • Bile neutralises the acid and makes the conditions alkaline so the enzymes can work properly.
      • Bile emulsifies fats which makes it into smaller droplets
        • This increases the surface area meaning the lipase enzyme has more to work on
    • Parts of the digestive system
      • Salivaryglands
        • Produce amylase in the saliva
      • Stomach
        • Pummels the food with muscular walls
        • Produces pepsin (protease)
        • Produces hydrochloric acid to kill bacteria and the give the right pH for pepsin
      • Liver
        • Bile is produced
      • Gall bladder
        • Bile is stored
      • Pancreas
        • Produces protease, amylase and lipase.
      • Small Intestine
        • Produces protease, amylase and lipase
        • Where digested food is absorbed into the bloodstream
      • Large intestine
        • Excess water from food is absorbed
      • Rectum
        • Where faeces is stored before leaving through the anus

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