What Are Enzymes?

• Enzymes are:

  • Catalysts that speed up the rate of a chemical reaction without being changed or used up in the reaction

  • Proteins

  • Biological catalysts (biological because they are made in living cells, catalysts because they speed up the rate of chemical reactions without being changed)

  • Necessary to all living organisms as they maintain reaction speeds of all metabolic reactions (all the reactions that keep an organism alive) at a rate that can sustain life

    • For example, if we did not produce digestive enzymes, it would take around 2 - 3 weeks to digest one meal; with enzymes, it takes around 4 hours

Enzymes are specific to one particular substrate (molecule/s that get broken down or joined together in the reaction) as the enzyme is a complementary shape to the substrate

• The product is made from the substrate(s) and is released

Investigating the Effect of Temperature on Amylase

• Starch solution is heated to a set temperature

• Iodine is added to wells of a spotting tile

• Amylase is added to the starch solution and mixed well

• Every minute, droplets of solution are added to a new well of iodine solution

• This is continued until the iodine stops turning blue-black (this means there is no more starch left in the solution as the amylase has broken it all down)

• Time taken for the reaction to be completed is recorded

• Experiment is repeated at different temperatures

• The quicker the reaction is completed, the faster the enzyme is working