GCSE Science Enzymes

GCSE Science Enzymes

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  • they are proteins
  • biological catalysts - increases rate of reaction
  • each enzyme is specific to substrate 
  • substrates are changed into products
  • lock and key theory
  • each enzyme is a different shape
  • within enzyme - active site
  • only one substrate fits into the active site 
  • enzymes can be denatured 
  • if shape changes then substrate can't fit into active site 
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Enzymes (Continued)

  • they speed up reactions, lowering 'activation energy'
  • 'activation energy' needed to start reaction
  • factors that affect rate of reaction:
  • temperature, pH, enzyme concentration, substrate concentration, surface area and pressure 
  • optimum - where enzymes work best at one particular temperature 
  • when enzyme is denatured - temp and pH is not right, causes enzyme to change (irreversibly) affects shape of active site
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Enzymes Summary

  • enzymes speed up the rate of reaction
  • enzymes are specific because they only work on one substrate 
  • the substrate fits into the active site of the surface of the enzyme
  • enzymes can be re-used so only small amounts are needed
  • enzymes belong to a group of chemical compounds called proteins 
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