enzymes introduction

• catalyst

  a substance that increases the speed of a reaction without being changed or used up in the process
• an enzyme is made up by living organisms so they are referred to as biological catalysts.
• enzymes themselves are basically just large proteins so are made up of long chains of amino acids. depending on the sequence of the amino acids in the chains they can fold up to make different shapes and each of these shapes would be a unique enzyme
• active site

  part of an enzyme with a unique shape that is complementary to the substrates of the reaction
• if a substrate does not fit the active site of the enzyme the reaction wont be catalysed. this allows the enzymes to be really specific about which reactions they speed up
• lock and key model


  scientists thought that the substrate had to fit perfectly into the active site
• induced fit model


  the enzyme changes shape slightly as it binds to the substrate. the active site is complementary to the substrate