Enzymes and Digestion

• Enzymes are biological catalysts.
• Only enzyme found in the stomach is protease (pepsin).
• Reasons why hydrochlric acid is in the stomach:

  • They kill bacteria.
  • Creates the right environment for the enzymes to work on.
• Bile:

  • Emulsifies lipid droplets which gives them a larger SA for enzymes to break them down.
  • They are a strong alkali which can make them neutralise stomach acid.
  • They are produced in the liver and stored in the gall bladder.
• Amylase enzyme works on starch which then produces glucose.
• Protease enzyme works on protein and produces amino acids.
• Lipase enzyme works on fats (lipids) and produces free fatty acids and glycerol.
• To test for poteins, you use biruret solution which will turn purple if proteins are present.
• To test for sugar, you use heated (heated via water bath) benedict solution/reagent, which will turn either red, yellow, green (colour depends on concentration of sugar) if sugar is present.
• To test for starch, you use iodine solution which will turn blue / black if starch is present.
• Action sites for amylase:

  • Mouth
  • Small Intestine.
• Amylase can be produced in:

  • Small intestine.
  • Pancreas.
  • Salivary glands.
• Protease can be produced in:

  • Pancreas.
  • Stomach.
  • Small intestine.
• Action sites for protease:

  • Small intestine.
  • Stomach.
• Small intestine:

  • Produces digestive enzymes (protease, amylase etc).
  • Digests food.
  • Absorbs soluble food molecules.
• Advantages and disadvantages of using ezymes in washing powders:

  • Enzymes are effective at removing cells.
  • Enzymes can be used at low temperatures, saving energy and costs.
  • Enzymes may enter natural water sources which could cause pollution.
  • Enzymes could digest material of clothing.
• 2 main roles of digestion:

  • Breaking down bigger food molecules into smaller soluble food molecules.
  • Absorption, absrobing the food molecules into the body.
• How does increasing the temperature causes enzymes to denature:

  High temps break the bonds holding the enzymes together, which causes the enzyme and the active site to change shape whcih means the enzymes active site won't be complementary to its substrate.