Class XII Practical: Biochemical & Physiological Experiments - Effect of Enzyme Action (Temperature & pH) on Starch Breakdown

Objective

To investigate the effect of varying temperature and pH on the activity of an enzyme (e.g., amylase) in breaking down starch.

Guidelines

1. Reagent Preparation: Prepare starch solution, amylase solution, and buffer solutions of different pH values.
2. Temperature Experiment:
   • Set up multiple test tubes, each containing starch solution and amylase solution.
   • Incubate these test tubes at different temperatures (e.g., 0°C, 20°C, 37°C, 60°C, 100°C) using water baths.
   • At regular intervals, take a drop from each test tube and test for the presence of starch using iodine solution. Note the time taken for starch to disappear (endpoint).
3. pH Experiment:
   • Set up multiple test tubes, each containing starch solution, amylase solution, and a buffer solution of a specific pH (e.g., pH 4, 6, 7, 8, 10).
   • Maintain a constant optimal temperature (e.g., 37°C).
   • At regular intervals, test for starch presence using iodine solution and note the time taken for starch to disappear.
4. Data Analysis: Plot graphs showing enzyme activity (e.g., 1/time taken for starch disappearance) against temperature and pH.

Expected Outcome

Demonstration of optimal temperature and pH for enzyme activity, and how deviations from these conditions lead to decreased enzyme efficiency or denaturation.