• Created by: akv1234
  • Created on: 19-03-17 17:59


  • Enzymes are biological catalysts as they have the organic substances needed to speed up reactions while remaining unchanged


  • They are made of protein

  • They are very specific to their substrate

  • They can join small molecules or break down large molecules

  • They can do this with lower activation energy than if the enzyme was not used

  • The substrate fits into the active site like ‘lock and key’ a hypothesis

  • The induced fit model suggests the same idea of a lock and key hypothesis, except that the active site slightly changes to ensure a snug fit of the substrate.

Factors that affect rate of enzyme reaction

  • Temperature

    • At low temperatures reaction is slow

    • An increase of 10° C doubles the rate of reaction

    • Every enzyme has a different optimum temperature - mammals 37-40° C

    • A slight increase about the optimum (usually up to 50°C will slow down the rate of reaction.

    • At high temperatures, the enzyme will be denatured and its active site will be permanently altered due to intense kinetic energy.

  • Enzyme concentration

    • The more enzyme molecules there are the more active sites there are to act on the substrate molecules

    • Therefore an increase in enzyme concentration increases to rate of reaction

  • Substrate concentration

    • The more substrate molecules there are the


No comments have yet been made