Anaerobic respiration occurs when oxygen is limited or absent. During anaerobic respiration in plant cells, glucose is partially broken down into ethanol and carbon dioxide, rather than being fully oxidized to carbon dioxide and water. The experiment measured the production of carbon dioxide gas over time from yeast fermenting different concentrations of glucose solutions (5%, 10%, 15%). Higher glucose concentrations produced more carbon dioxide, with the 15% solution producing the most.

1. Anaerobic
respiration:
Fermentation
I can live without YOU!

2. Scientific Concept:
Anaerobic respiration occurs in conditions of limited
oxygen supply or in the absence of oxygen.
During anaerobic respiration, the glucose is not fully
oxidised to carbon dioxide and water but partly
disintegrates into ethanol and carbon dioxide in
plant cells.
C6H12O6 --------------> 2C2H5OH + 2CO2 + 2ATP

3. ENGAGE
What are the important ingredients do you need to make a bun?
What makes the dough expand and becomes bigger?
How to control the bun expand and becomes bigger in the
shortest time?

4. EMPOWER
Carbon dioxide
sensor
Glucose and yeast
mixture solution
Water bath

5. Procedure:
1. Measure 4 grams of yeast by the electronic balance.
2. Prepare 3 different concentration of glucose solutions as follows:
5%, 10% and 15%
3. Boil all the glucose solutions under the Bunsen flame to
evaporate any dissolve oxygen in the solution.
4. Cool down the glucose solutions by the ice to prevent the heat
produced killed the yeast during the fermentation.
5. Connect the carbon dioxide sensor with the Data Logger.

6. 6. Mix the glucose solutions with the yeast in the reagent bottle
under the water bath with temperature 30oC.
7. Add a layer of oil on the top of the solutions to prevent gas trap
on the solution.
8. Seal the carbon dioxide sensor to the reagent bottle of the
mixed solution.
9. Put the reagent bottle under the water bath for 10 minutes.
10. Record the amount of carbon dioxide at each 10 second
interval.

7. Results
Graph of Amount of CO2 Produced Versus Time
5%
10%
15%

8. Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
0 738.462 590.769 758.154
10 718.769 600.615 758.154
20 738.462 580.923 748.308
30 738.462 600.615 768
40 708.923 590.769 748.308
50 728.615 610.462 768
60 708.923 590.769 768
70 738.462 610.462 768
80 718.769 600.615 777.846
90 748.308 600.615 777.846
100 738.462 620.308 797.538
110 738.462 610.462 768
120 758.154 620.308 807.385
130 748.308 610.462 797.538
140 768 640 777.846
150 738.462 630.154 807.385
Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
160 777.846 630.154 787.692
170 758.154 649.846 807.385
180 777.846 630.154 787.692
190 777.846 649.846 807.385
200 768 640 807.385
210 787.692 649.846 807.385
220 768 649.846 836.923
230 797.538 640 836.923
240 777.846 669.538 896
250 797.538 649.846 905.846
260 777.846 669.538 935.385
270 807.385 640 974.769
280 817.231 679.385 984.615
290 807.385 669.538 1014.154
300 827.077 669.538 1014.154

9. Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
310 807.385 689.231 1043.692
320 836.923 679.385 1053.538
330 817.231 689.231 1063.385
340 846.769 689.231 1083.077
350 836.923 699.077 1083.077
360 827.077 708.923 1112.615
370 856.615 689.231 1102.769
380 836.923 728.615 1132.308
390 856.615 708.923 1161.846
400 846.769 748.308 1152
410 876.308 728.615 1191.385
420 856.615 748.308 1191.385
430 866.462 768 1220.923
440 886.154 758.154 1220.923
450 866.462 787.692 1250.462
Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
460 896 787.692 1289.846
470 876.308 807.385 1289.846
480 896 807.385 1309.538
490 876.308 827.077 1309.538
500 905.846 836.923 1358.769
510 896 817.231 1368.615
520 896 846.769 1358.769
530 925.538 827.077 1408
540 905.846 846.769 1417.846
550 925.538 836.923 1457.231
560 915.692 846.769 1447.385
570 935.385 866.462 1476.923
580 925.538 846.769 1516.308
590 955.077 876.308 1536
600 945.231 856.615 1585.231

10. Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
610 945.231 876.308 1595.077
620 974.769 866.462 1624.615
630 964.923 876.308 1634.462
640 994.462 886.154 1654.154
650 974.769 876.308 1693.538
660 1024 896 1693.538
670 1004.308 866.462 1742.769
680 1014.154 905.846 1762.462
690 1033.846 896 1801.846
700 1024 905.846 1831.385
710 1053.538 915.692 1841.231
720 1043.692 905.846 1910.154
730 1073.231 935.385 1920
740 1043.692 915.692 1979.077
750 1083.077 945.231 1979.077
Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
760 1073.231 925.538 1998.769
770 1083.077 945.231 2048
780 1112.615 955.077 2048
790 1102.769 945.231 2107.077
800 1142.154 974.769 2126.769
810 1132.308 955.077 2176
820 1161.846 974.769 2205.538
830 1142.154 974.769 2254.769
840 1181.538 994.462 2313.846
850 1191.385 1014.154 2323.692
860 1191.385 1004.308 2382.769
870 1220.923 1024 2392.615
880 1211.077 1024 2432
890 1240.615 1063.385 2471.385
900 1240.615 1053.538 2481.231

11. Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
910 1270.154 1083.077 2520.615
920 1260.308 1083.077 2530.462
930 1270.154 1083.077 2599.385
940 1309.538 1102.769 2609.231
950 1299.692 1092.923 2668.308
960 1348.923 1112.615 2737.231
970 1329.231 1092.923 2766.769
980 1358.769 1112.615 2825.846
990 1348.923 1132.308 2825.846
1000 1398.154 1112.615 2894.769
1010 1388.308 1122.462 2904.615
1020 1398.154 1112.615 2934.154
1030 1437.538 1142.154 3003.077
1040 1427.692 1132.308 3042.462
1050 1467.077 1142.154 3101.538
Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
1060 1447.385 1161.846 3131.077
1070 1486.769 1142.154 3200
1080 1467.077 1161.846 3249.231
1090 1486.769 1152 3268.923
1100 1516.308 1181.538 3318.154
1110 1506.462 1161.846 3347.692
1120 1536 1171.692 3396.923
1130 1526.154 1191.385 3436.308
1140 1555.692 1181.538 3475.692
1150 1545.846 1191.385 3554.462
1160 1575.385 1181.538 3574.154
1170 1565.538 1211.077 3662.769
1180 1575.385 1191.385 3712
1190 1604.923 1220.923 3780.923
1200 1595.077 1230.769 3830.154

12. Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
1360 1772.308 1408 4736
1370 1801.846 1388.308 4775.385
1380 1801.846 1417.846 4883.692
1390 1831.385 1398.154 4962.462
1400 1831.385 1398.154 5021.538
1410 1860.923 1417.846 5060.923
1420 1880.615 1408 5041.231
1430 1880.615 1437.538 5060.923
1440 1920 1417.846 5041.231
1450 1900.308 1447.385 5060.923
1460 1939.692 1427.692 5060.923
1470 1939.692 1427.692 5041.231
1480 1969.231 1447.385 5060.923
1490 1959.385 1437.538 5041.231
1500 1988.923 1457.231 5060.923
Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
1210 1634.462 1230.769 3869.538
1220 1614.769 1260.308 3928.615
1230 1634.462 1250.462 3948.308
1240 1624.615 1270.154 4017.231
1250 1654.154 1270.154 4056.615
1260 1673.846 1289.846 4135.385
1270 1654.154 1319.385 4214.154
1280 1693.538 1319.385 4263.385
1290 1683.692 1358.769 4361.846
1300 1713.231 1339.077 4401.231
1310 1703.385 1378.462 4460.308
1320 1732.923 1368.615 4489.846
1330 1732.923 1378.462 4548.923
1340 1752.615 1388.308 4617.846
1350 1782.154 1378.462 4657.231

13. Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
1660 2274.462 1821.538 5041.231
1670 2294.154 1841.231 5060.923
1680 2304 1880.615 5041.231
1690 2343.385 1959.385 5060.923
1700 2343.385 2028.308 5051.077
1710 2382.769 2087.385 5041.231
1720 2392.615 2097.231 5060.923
1730 2441.846 2156.308 5041.231
1740 2441.846 2166.154 5060.923
1750 2481.231 2205.538 5041.231
1760 2520.615 2284.308 5060.923
1770 2550.154 2333.538 5060.923
1780 2619.077 2422.154 5051.077
1790 2638.769 2481.231 5060.923
1800 2707.692 2530.462 5041.231
Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
1510 2008.615 1457.231 5041.231
1520 2008.615 1486.769 5041.231
1530 2048 1476.923 5060.923
1540 2038.154 1496.615 5041.231
1550 2077.538 1536 5060.923
1560 2067.692 1536 5041.231
1570 2097.231 1595.077 5060.923
1580 2107.077 1624.615 5060.923
1590 2116.923 1683.692 5041.231
1600 2146.462 1703.385 5060.923
1610 2136.615 1713.231 5041.231
1620 2185.846 1742.769 5060.923
1630 2185.846 1752.615 5041.231
1640 2225.231 1782.154 5051.077
1650 2235.077 1792 5060.923

14. Time(s) CO2 I/O-1(ppm) CO2 I/O-2(ppm) CO2 I/O-3(ppm)
1810 2727.385 2550.154 5070.769
1820 2806.154 2589.538 5051.077
1830 2855.385 2658.462 5051.077
1840 2924.308 2727.385 5060.923
1850 3003.077 2845.538 5041.231
1860 3042.462 2924.308 5060.923

15. Questions
1. Look at your table ,why does the carbon dioxide level
change?
2. Base on the graph, which fermentation of glucose
produced higher amount of carbon dioxide gas? Why?
3. Calculate the rates of respiration of each concentration of
glucose by using the formula given below.
4. What can you conclude from this experiment?
Rate of respiration =
Final reading- initial reading
Time (min)

16. Answer
1. The change of carbon dioxide level indicated that the yeast fermentation of
glucose have begun. Or anaerobic respiration has initiated by yeast.
2. In the same period of time, fermentation of yeast in glucose 5% have
produced higher amount of carbon dioxide. This can be explain as in high
concentration of glucose such as 10% and 15%, the increase in glucose
concentration led to in the increase in fermentation time. Besides, when
the glucose content increased, the glucose uptake rate decreased, this will
affect the rate of fermentation. Thus, as longer time is required for
fermentation of yeast to occur, it have reduced the amount of CO2
produced for both 10% and 15% of glucose fermentation.
4. Fermentation of different concentration of glucose will have different rate
of fermentation and different amount of end product in fixed time.

17. ENHANCE
In the production of fruit wine, most fruits have
natural sugar in them and without adding extra
sugar, these can be turned into a wine of about 4%
to 6% volume alcohol. This is a low alcohol content.
How high alcohol content of fruit wine is produced?

18. Unique Feature of This Activity
1. Amounts of carbon dioxide produced can be detected and
measured accurately. We can measure in every 10 seconds and
the data can be recorded up to three decimal places.
2. Less work need to be done by the students. For example,
students do not need to be with the experiment all the time as
the results will be recorded automatically during that period of
time.
3. The pattern of amount of CO2 production changes can be
observe along with the experiment.
4. The changes of the data in table and graph can be observed
immediately, allowing us to halt and repeat the experiment
easily.