core practical pH and enzymes

• This is a practical video on investigating the effect of pH on enzyme activity
• The enzyme used is amylase, which catalyzes the breakdown of starch into smaller sugar molecules
• The iodine test identifies the presence of starch but does not react with simple sugars
• Experimental procedure

  1. Measure 2 cm³ of amylase solution into a test tube

  2. Add 1 cm³ of pH solution to the test tube

  3. Record the pH of the solution

  4. Add 2 cm³ of starch solution to the test tube

  5. Start the stop clock

  6. Take a small amount of the mixture and place a drop on the first iodine spot on the tile

  7. Return the rest of the solution to the test tube

  8. If the iodine turns black, wait 10 seconds before testing again

  9. Repeat the testing at 10 second intervals
• Repeat the experiment using solutions with different pH values to obtain a range of data
• Try to repeat the experiments to obtain more accurate mean values at each pH