Yeast Fermentation Essay Example for Free

Yeast Fermentation Essay The aim of this experiment was to investigate the effect of different amounts of a substrate on the respiration rate of yeast and to compare this to the effect of different amounts of glucose on the rate of yeast respiration. The substrate which I chose to further investigate was fructose. Fructose is a fruit sugar which is one of the three, along with glucose and galactose, dietary monosaccharides that are directly absorbed into the bloodstream during digestion. Materials: 2% yeast solution Large beaker Small beaker Conical flask Thermometer (Ë™C) Glass rod pH meter data logger Hot water Sensitive digital scale (g) Fructose (1.0g, 1.5g, 2.0g, 2.5g) Glucose (1.0g, 1.5g, 2.0g, 2.5g) Measuring cylinder (cm3) Variables Independent: Concentration of glucose (1.0g, 1.5g, 2.0g, 2.5g) , concentration of fructose (1.0g, 1.5g, 2.0g, 2.5g) Dependent: Amount of carbon dioxide produced, i.e. rate of yeast respiration Controlled: 2% yeast solution (20cm3), initial temperature of yeast solution (35-40Ë™C), amount of time that the reaction is measured (180 seconds) Method †¢20cm3 of yeast solution was measured using a measuring cylinder and then  poured into a conical flask. †¢1.0g of glucose was weighed on a digital balance. †¢Hot wà ¡ter was poured into a large beaker, and the conical flask containing the yeast was placed inside with a thermometre inside. †¢The conical flask was kept inside The conical flask was held like this until the 2% yeast solution reached an initial temperature between 35-40Ë™C (specific temperature was noted down) When this temperature was reached, the thermometer was taken out of the conical flask and the conical flask out of the hot wate