ENZYMES

ENZYMES

1. enzymes are catalysts produced by living things - work as biological catalysts

   • Organisms have chemical reactions going on inside them all the time which need to be controlled to get the right amount of substances
     • raising temperature usually speeds up reactions, unfortunately the bad ones too however if it goes too high cells can get damaged(denatured)
       • enzymes reduce the need for temperature rise and only speed up useful chemical reactions
         • enzymes are all proteins and proteins are chains of amino acids these chains are folded into unique shapes which enzymes need to do their job
           • As well as catalysts proteins act as structural components of tissues E.g muscles, hormones and antibodies
   • catalysts increases reaction speed without being changed or used up in the reaction

2. Enzymes have special shapes to catalyse reactions

   • every enzyme has a unique shape which fits onto the substance in a reaction
     • enzymes are very selective and usually only catalyse 1 reaction
       • Because for the enzyme to work the substance has to fit its special shape if the substance doesn't match the reaction won't be catalysed
   • chemical reactions usually involve something being split or joined together

3. Enzymes need the right temperature and pH

   • changing temperature changes the rate of an enzyme catalysed reaction
     • increasing temperature increases reeaction rate however if it gets too hot some bonds holding the enzyme together break destroying the enzymes special shape and so won't work anymore (denaturing)
       • enzymes in the body normally work best around 37 degrees celsius
   • pH also affects enzymes if it's too high or low the pH interferes with the bonds holding the enzyme together which changes the shape and denatures the enzyme
     • all enzymes have an optimum pH, they work best at its often pH 7 however for example Pepsin breaks proteins down in the stomach it works best at pH 2 so is well suited for the acidic conditions there