P: Enzymes and PH

• What is the aim of the experiment described in the study material?

  To investigate the effect of changes in pH on amylase activity
• What substrate is used to measure amylase activity in the experiment?


  Starch
• What is the product of the reaction catalyzed by amylase?


  Maltose
• What equipment is needed for the experiment?

  • Test tubes
  • Test tube rack
  • Water baths
  • Spotting tiles
  • Measuring cylinders
  • Syringes
  • Glass rod
  • Stopwatch
  • Starch solution
  • Amylase solution
  • Buffered solutions
  • Iodine solution
  • Thermometer
• What is the first step in the method for testing pH?


  Label each well with the time and add a drop of iodine solution
• How much buffer solution should be added to each test tube?


  2 cm​3
• At what temperature should the starch solution, amylase solution, and buffer solutions be equilibrated?


  25​°C
• What should be done immediately after adding starch to the test tube with amylase?


  Start timing immediately
• How is the rate of enzyme reaction calculated?


  By using \( \frac{1}{\text{time taken for iodine solution to remain brown}} \)
• What should be done after completing the tests with one pH value?


  Repeat steps 2-8 for buffer solutions with different pH values
• What is the relationship between pH and the rate of enzyme reaction in this experiment?


  • The rate of enzyme reaction is measured against different pH values.
  • A graph is plotted to visualize the effect of pH on amylase activity.
• What is a potential source of error in the experiment?


  The intervals between testing samples may be too long
• What safety precautions should be taken during the experiment?

  Wear safety goggles and tie back long hair when using hot water and Bunsen burners
• What should be done if using a Bunsen burner during the experiment?


  Tie long hair back and wear goggles
• What should be worn when using iodine solution?

  Safety goggles
• What is the purpose of the iodine solution in the experiment?


  To indicate the presence of starch
• What does it mean if the iodine solution remains brown?


  It indicates that starch has been completely broken down
• How does the method ensure accurate measurement of amylase activity?


  By using consistent timing and controlled pH conditions