Biology – Mode of action of enzymes | e-Consult

Method:

1. Catalase Preparation: Prepare a catalase extract by grinding fresh potato (or other suitable source) with distilled water. Filter the mixture through several layers of muslin to obtain a catalase solution. The concentration of the catalase solution should be kept constant for all trials.
2. Hydrogen Peroxide Solution: Prepare a solution of hydrogen peroxide (H₂O₂) of a known concentration (e.g., 3%).
3. Reaction Setup: Set up a system where the hydrogen peroxide solution is mixed with the catalase solution. A suitable apparatus would involve a flask containing the catalase solution, with a delivery tube leading to a graduated conical flask. The conical flask will collect the oxygen gas produced as a product.
4. Rate Measurement: Measure the volume of oxygen gas produced over a fixed time interval (e.g., 1 minute) for several trials. The volume of oxygen can be determined by measuring the displacement of water in the conical flask. Repeat the experiment at different temperatures (e.g., 10°C, 20°C, 30°C, 40°C) to investigate the effect of temperature on the reaction rate.
5. Control Variables: Crucially, maintain constant:

   • Catalase concentration
   • Hydrogen peroxide concentration
   • Volume of catalase solution
   • Temperature
   • Volume of hydrogen peroxide solution

Variables to Investigate: The independent variable is temperature. The dependent variable is the rate of oxygen production (volume of O₂ produced per minute).

Constant Conditions: Maintain constant temperature using a water bath. Ensure the same volume of hydrogen peroxide and catalase are used in each trial. Use the same type and concentration of catalase extract. Ensure the same apparatus is used for each trial.