What is Anaerobic Respiration? This is a kind of respiration which do not require any oxygen. Only some of the organisms can perform anaerobic respiration, e.g. Certain bacteria and fungi. In anaerobic respiration, glucose is only partly broken down. Much less energy is produced since there is no oxygen, so the reaction can not carry out completely by entering the electron system in order to produce more ATP.

Glucose Energy + Ethanol + Carbon Dioxide THIS IS THE WORD EQUATION!

C 6 H 12 O 6 ATP + CH 3 CH 2 OH + CO 2 THIS IS THE CHEMICAL EQUATION!

Alcoholic fermentation is the basis of brewing and wine making. But ethanol is toxic to yeast. We conduct this experiment to investigate the effect of concentration of ethanol on anaerobic respiration of yeast. What is our aim to conduct the experiment??

We estimated that the respiration rate will decrease with the increasing concentration of ethanol. Since ethanol is poisonous, as the concentration of ethanol increase, the yeast will be inhibited to carry out respiration and hence the respiration rate of yeast will decrease gradually. Some of the yeast may die because ethanol is toxic to yeast.

1.Setup the computer and get Science Workshop ready 2.5 syringes and beakers areprepared,and labelled 1,2,3,4 and 5 3.Mix pure ethanol anddistilled water according to table below into a beaker Percentage of ethanol solution (%) Volume of water (cm 3 ) Volume of ethanol (cm 3 ) Volume of glucose (cm 3 ) 1.25

The Setup for the Experiment

1.Some gas may enter through the linkages and the yeast may perform aerobic respiration. 2.Leakage of gas may occur, the pressure is not accurate. 3.The concentration of ethanol solution is not exact because measuring cylinder is used. 4.The pressure change is very small, the pressure sensor may be very sensitive.

By: Herby Cheung (5) Margaret Ng (19) Karen Wong (24) 6AS Celene Ho (13) 6B