Enzyme Investigations | Biology for GCSE/IGCSE - Year 11 PDF Download

Investigating the Effect of Temperature on Amylase

• Starch solution undergoes heating to a predetermined temperature.
• Iodine solution is dispensed into wells on a spotting tile.
• Amylase is introduced into the starch solution and thoroughly mixed.
• At intervals of one minute, small amounts of the mixture are transferred into separate wells containing iodine solution.
• This process continues until the color change of the iodine solution ceases, indicating the absence of starch due to its breakdown by the amylase.
• The duration of the reaction is recorded as the time taken for completion.
• The experiment is replicated across various temperatures.
• A faster completion of the reaction signifies higher enzyme activity.

Investigating the Effect of pH on Amylase

• Place drops of iodine solution on a tile in rows.
• Label a test tube with the pH level to be tested.
• Use a syringe to add 2cm³ of amylase into the test tube.
• Add 1cm³ of buffer solution to the test tube using a syringe.
• In a separate test tube, combine 2cm³ of starch solution with amylase and buffer solution. Start the stopwatch while mixing using a pipette.
• After 10 seconds, apply a drop of the mixture on the first iodine drop, observing a color change to blue-black.
• Wait another 10 seconds, then place a drop of the mixture on the second iodine drop.
• Continue this process every 10 seconds until the iodine solution remains orange-brown.
• Repeat the experiment at various pH levels. The quicker the iodine solution turns orange-brown, the more efficiently the enzyme works at that pH.