effect of pH on amylase

• What is amalyse?

  An enzyme that breaks starch down into simple sugar
• What is iodine used to test for?

  Presence of starch
• What colour does iodine become with the presence of starch?

  Blue/Black
• Materials needed for finding the effect of pH on amalyse


  - 3 test tubes

  - Water bath

  - Amalyse solution

  - Starch solution

  - pH 5 buffer solution

  - iodine

  - stirring rod

  - Spotting tiles
• Method for finding the effect of pH on amalyse


  1. Put iodine into each well of a spotting tile

  2. Take 3 test tubes putting:2cm3 of starch solution2cm3 of Amalyse solution2cm3 of pH 5 buffer solution

  3. Place all 3 test tubes into a waterbath of 30C

  4. Leave for 10 mins -So all teach same temperature

  5. Combine all 3 solutions by pouring into one test tube and mixing with stirring rod

  6. Return to waterbath and start a stopwatch

  7. After 30 seconds use the stirring rod to transfer 1 drop of the solution to one of the wells containing iodine

  8. Look for blue/black reaction

  9. Repeat this experiment every 30 seconds untill no reaction occurs, record the time

  10. Repeat experiment at different pHs
• What are put into the 3 test tubes in the effect of pH on amalyse Practical?

  • 2cm3 starch solution
  • 2cm3 amylase solution
  • 2cm3 pH 5 buffer solution
• What is a Buffer soluton?

  A solution used to control pH
• Why do you stop and record results when no reaction occurs with solution and iodine in the effect of pH on amalyse Practical?

  When no reaction occurs between the two it means that starch is no longer present - which means that the reaction has completed between the amalyse and starch
• What are the problems with the effect of pH on amalyse practical?

  The solution is only tested every 30 seconds

  - This means the time recorded for the reaction completed is only approximate- The solution to this is totest the solution every 10 seconds

  The colour change from black to orange between solutions is gradual

  - This means it is hard to tell when the reaction is completed and to record the time- The solution is to get many opinions on when the reaction is completed and then democratically deciding