Investigation of the effect of pH on enzyme activity (LC 2026) (Leaving Cert Biology): Revision Notes
📚 Revision Notes
Investigation of the effect of pH on enzyme activity
Materials needed:
- Hydrogen Peroxide (substrate)
- Celery (contains enzyme catalase)
- pH buffer (vary 4,7,10,13)
- Temperature (keep temperature constant 30°C)
- Washing up liquid
- Graduated cylinders
- Plastic droppers
Method:
- Place 10cm³ of celery, one drop of washing up liquid and 10cm³ of pH buffer 4 in a graduated cylinder.
- Add 5cm³ of hydrogen peroxide to another graduated cylinder.
- Place both graduated cylinders in a thermostatically controlled water bath set at 30°C for 2 minutes to allow all reagents to reach the exact temperature.
- After 2 minutes, add the hydrogen peroxide to the graduated cylinder containing the other reagents.
- Record the volume of foam produced after 2 minutes. The foam volume measures enzyme activity by indicating the amount of oxygen produced.
- Repeat the experiment at pH 7, 10, 13.
- Record results and plot a graph of results, putting temperature on the x-axis (horizontal) and volume of foam (cm³) on y-axis (vertical).
Results:
| pH | 4 | 7 | 10 | 13 |
|---|---|---|---|---|
| Volume of foam cm³/ 2 minutes | 0cm³ | 0cm³ | 13cm³ | 0cm³ |
Graph of Results:
