Investigating Anaerobic Respiration In Yeast 5943l

Investigating anaerobic respiration in yeast Problem statement: what are the product of fermentation? Procedure : 1. Prepare 2 boiling tube and label it boiling tube A and B 2. boiling tube A is filled with 5 ml of yeast suspension and 15 ml of boiled glucose solution 3. boiling tube B is filled with only 15 ml of boiled glucose solution 4. A thin layer of paraffin oil is put on top of the contents of both boiling tubes 5. boiling tubes are corked with stoppers with delivery tubes 6. the end of each delivery tube is placed into a test tube filled with 2 ml of lime water 7. the initial temperatures of the contents in both boiling tubes are recorded 8. the apparatus is left aside for one hour 9. after one hour, the final temperatures are recorded and the change in lime water is noted 10. the stoppers are removed and any smell that is released from the boiling tubes is noted 11. the results are recorded in the table

results Boiling tube

A

B

At the beginning of At the end of the the experiment experiment

At the beginning of At the end of the the experiment experiment

Temperature (C)

30

31

30

30

Lime water

clear

cloudy

clear

Clear

Smell

Smell of ethanol is Smell of ethanol is Smell of ethanol is Smell of ethanol is not detected detected not detected not detected

Discussion 1. an aerobic condition occurs when a glucose solution is boiled and paraffin oil is added to cover the glucose solution. This prevent air from dissolving in the glucose solution. The glucose solution is boiled to remove dissolved oxygen 2. test tube B is set up as a control experiment 3. after one hour the contents of boiling tube A are cloudy and foamy whereas the contents of boiling tube B remain clear and non foamy 4. anaaerobic respiration occur in boiling tube A because the lime water in test tube A turns cloudy, the temperature of the contents increases and the smell of ethanol is detected 5. the cloudy lime water indicates the presence of carbon dioxide. The increase in temperature indicates that heat energy is released. The semll of ethanol confirms that anaerobic respiration has taken place in boiling tube A. 6. the process that has taken place in boiling tube A is fermentation. 7. Fermentation by yeast produces ethanol, carbon dioxide and energy conclusion in the absence of oxygen, yeast undergoes anaerobic respiration to produce

carbon dioxide, ethanol and energy. The hypothesis is accepted