The role of Enzymes and Food tests

• Why can enzymes be decided as biological catalysts?

  They have a high affinity for the substrate
• Why do enzymes only usually cataylse one reaction?

  Because they have specific shape that go with specific substrate
• What does it mean when an enzyme has been denatured?

  Loss of its structure and function due to a change in environment e.g temperature
• To investigate the effect of pH on the rate of amylase activity:
• Amylase breaks down carbohydrates starch molecules
• Mix 1cm^3 of amylase with buffer solution
• Place the mixture in water to maintain a constant temperature and heat it on a Bunsen burner
• Add starch solution to the beaker and start the stopwatch
• Every 30 seconds, take a sample of the mixture with a pipette and drop it into a well in a spotting tile with iodine
• If the mixture turns black, starch is still present; if it doesn't, it has been broken down by the amylase - note down the time
• Repeat the experiment with different pH buffers
• list the three places where amylase is made in the human body:

  salivary glands pancreas small intestine
• What is the role of lipases?

  convert Lipids into Glycerol and fatty acids
• Where is bile stored?

  Gallbladder
• Name the solution that you would use to test for the presence of lipids in a food sample: Ethanol or the Sudan III test