Enzymes Required Practical 5

• What is the aim of the experiment on the effect of pH on amylase activity?

  To determine the time taken for starch to be completely digested and calculate the rate of enzyme activity at different pH values.
• What equipment is needed for the experiment on amylase activity?

  • Test tubes
  • Test tube rack
  • Water baths (electrical or Bunsen burners and beakers)
  • Spotting tiles
  • 5 cm³ measuring cylinder
  • Syringes
  • Glass rod
  • Stopwatch
  • Starch solution
  • Amylase solution
  • Buffered solutions
  • Iodine solution
  • Thermometer
• Why is it important to label each well with time during the experiment?

  To track the time taken for starch digestion at each interval.
• How much buffer solution should be added to each test tube?

  2 cm³
• 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.
• What is the purpose of rinsing the glass rod between tests?

  To avoid contamination of the samples.
• How is the rate of enzyme reaction calculated?

  By using 1/time taken for iodine solution to remain brown
• What steps should be repeated for buffer solutions with different pH values?

  1. Add 2 cm³ of each buffer solution to test tubes.
  2. Immerse the starch and amylase solutions in a water bath.
  3. Add amylase and starch to the buffer solution and start timing.
  4. Transfer drops to the well and observe the color change.
• What should be plotted after conducting the experiment?

  • A graph of the rate of enzyme reaction against pH.
• What is a potential source of error in the experiment?

  Intervals between testing may be too long to accurately find when starch is completely broken down.
• What is a potential hazard when conducting the experiment?

  Be careful using hot water.
• What safety precaution should be taken if using a Bunsen burner?

  Keep long hair tied back and wear goggles.