1. Label two graduated cylinders as follows: ‘Water (control)’ and ‘Yeast (test)’.
2. Add 20 cm3 of a 10% glucose solution to each graduated cylinder.
3. Add 1 ml of water to the graduated cylinder labelled ‘Water (control)’.
4. Add 1 g of yeast to the graduated cylinder labelled ‘Yeast (test)’. 5. Swirl both cylinders carefully for 5–10 seconds. 6. Immediately record the volume of material in both cylinders.
7. Stand both graduated cylinders in a preheated 25 °C water bath for approximately 5 minutes. Observe changes in volume, if any.
8. Repeat steps 1–7 at the following temperatures: 0 °C, 10 °C, 40 °C, 60 °C. 9. Record your results.
Thermometer
Graduated cylinder
10% glucose solution
100 90 80 70 60 50 40 30 20 10
100 90 80 70 60 50 40 30 20 10
Yeast
SAFETY • Be careful when using the heated water bath.
Water Yeast
Mass balance Water bath (25 °C)
Thermometer
Water bath Mass balance 1 g
:Fig. 11.3 To investigate how temperature affects the rate of respiration j Go to page 28 of your Experimental Investigations Log to write up this investigation.