IB Biology, Enzymatic decomposition of hydrogen peroxide by enzyme catalase

IB Biology on Enzymatic decomposition of hydrogen peroxide by enzyme catalase using disc and well method

Simple enzymatic study (Inaccurate)

• Place 5ml hydrogen peroxide into well
• Soak paper disc in well containing catalase
• Place disc soak with catalase into well
• Measure time for disc to float
• H2O2 decomposes - produce O2
• O2 will cause the disc to float
• Rate = Time taken for disc to reach the surface

Accurate Method for Enzymatic study measured using Pressure or Oxygen sensor

• Rate of decomposition = Change in pressure due to release of O2 gas released over time
• Pressure sensor or Oxygen Sensor can be used
• Initial rate will have to be used

Click here to view video on decomposition of hydrogen peroxide using pressure sensor

• Make sure it is time based for 300s
• Press collect button to obtain the base line pressure
• Add catalase enzyme
• Close cap and measure pressure

Tip when using Pressure sensor

• Always collect the average rate for first 50s
• Use linear regression to find the gradient for first 50s
• If possible take instantaneous rate at time zero (Initial Rate)
• Initial rate (time close to zero) is used because as time progresses, conc of H2O2 changes
• To measure rate at certain H2O2 concentration - Initial rate must be use