Enzymes

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  • Created by: Lohita
  • Created on: 04-04-14 10:03
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  • Enzymes
    • Definition: Enzymes are biological catalysts
      • Catalysts are substances that increase the rate of chemical reactions without being used up
    • The active site of the enzyme is the part with a specific shape, where the substrate sits. The enzyme is specific to the substrate.
      • The shape of the active site allows this specificity.
        • If the shape of the enzyme changes, the active site may no longer work.
          • We say the enzyme has been denatured.
    • Factors affecting enzymes
      • Temperature: A reaction can happen at a quicker rate if the temperature is high
        • There is a limit to how far you can raise the temperature as the cells can get damaged.
          • This is called the optimum temperature.
            • Enzymes in the human body work at about 37 degrees.
      • pH: Changes in pH alter an enzyme's shape. Different enzymes work best at different pH values.
        • Enzymes in the stomach have an optimum pH of about 2.
    • Some enzymes work outside body cells
    • Biological and non-biological detergents
      • Biological:     - More effective at low temps than other types of detergents
        • - may contain protein-digesting and fat digesting enzymes (protease and lipase)
        • Advantages:  - Can be used at lower temperatures (environment)
          • - cheaper to run as less energy is used to increase temperature
        • Disadvantages: - affected by surroundings (pH)
          • - 40 degrees is the optimum temp, can't go higher as enzymes are denatured
            • - can cause skin irritation
      • Non-biological:      - does not contain enzymes which break down stain and dirt whilst in the wash
    • Enzymes in industry
      • Isomerase is used to convert glucose syrup into fructose syrup
        • Isomerase reduces sugar in people's diets and is used in slimming food
      • Protease is used in baby-food to 'pre-diges' some of the protein and it makes I easier for a baby's digestive system
      • Carbohydrase is used to convert starch into sugar (glucose) syrup and provides a cheap source of sweetness

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