Effect of pH on Amylase Activity

• What is the volume of amylase solution used in the experiment?

  1 cm³
• What is the volume of the pH buffer solution used?

  1 cm³
• What is the volume of starch solution added?

  5 cm³
• When is the starch solution added in the experiment?

  5 minutes after other solutions
• What does amylase enzyme do in this experiment?

  It breaks down starch
• At what temperature is the water bath set for the experiment?

  35 °C
• What should be done to investigate different pH levels?

  Repeat with different pH buffers
• How often is the mixture sampled during the experiment?

  Every 30 seconds
• What is used to sample the mixture?

  Dropping pipette
• What solution is used to test for starch?

  Drop of iodine solution
• Where is the iodine solution dropped for testing?

  On a spotting tile
• What is the independent variable in this experiment?

  pH of solution
• What is the dependent variable in this experiment?

  Time taken for amylase to break down starch
• What is the rate of reaction formula used in this experiment?

  Rate of reaction (s⁻¹) = time (s)
• What is the rate of reaction at pH 5?

  11.1 s⁻¹
• What is the time taken for amylase to break down starch at pH 6?

  30 seconds
• What is the time taken for amylase to break down starch at pH 7?

  60 seconds
• What is the time taken for amylase to break down starch at pH 8?

  More than 300 seconds
• How does the rate of reaction change with increasing pH from 5 to 6?

  The rate increases from 11.1 to 33.3 s⁻¹
• What trend is observed in the rate of reaction as pH increases from 5 to 7?

  The rate increases then decreases
• What can be inferred about amylase activity at pH 8?

  Amylase activity is very low or absent
• What are the steps involved in the experiment to measure amylase activity?

  1. Prepare amylase, pH buffer, and starch solutions.
  2. Add starch solution after 5 minutes.
  3. Sample the mixture every 30 seconds.
  4. Test for starch using iodine solution.
  5. Record time until browny-orange color remains.
  6. Analyze the effect of pH on amylase activity.
• What are the results of the experiment at different pH levels?

  • pH 5: 90 seconds, rate 11.1 s⁻¹
  • pH 6: 30 seconds, rate 33.3 s⁻¹
  • pH 7: 60 seconds, rate 16.7 s⁻¹
  • pH 8: >300 seconds, rate not measurable