Yeast Lab free essay sample

During this experiment we were trying to determine how food availability affects CO2 production (related to population growth). We investigated how one factor influences the change in yeast population growth as measured by the amount of carbon dioxide produced. The yeast that you buy in the store contains living organisms–invisible small one celled, microorganisms. As long as they are kept dry, they are inactive. When they are given food, moisture and warmth, they become active and carry out many of the life activities larger organisms do. Molasses, which you can also buy, is a mixture of substances that are obtained from sugar cane. Though the substances are not alive, they were made by living organisms, the sugar cane plants. Therefore, they are called organic substances. Organic substances as well as organisms themselves are Important to the work of biologists. The organic substances in molasses can be used as food by the yeasts. We will write a custom essay sample on Yeast Lab or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page The factors that can affect yeast growth are temperature (30 degrees Celsius is the optimum temp for yeast growth), nutrients (e. g. sucrose, fructose, glucose, lactose (does not affect yeast growth), pH level (5 6 is the optimum pH level for growth). Fermentation is the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat. These things relate to our experiment because yeast is a vital component in this experiment In this experiment we were assigned groups in which we worked in and made a hypothesis. The hypothesis the my group and I came up with was that ‘If different amounts of molasses were tested for yeast population then the 25% molasses solution would produce the most yeast because the more the amount of molasses then the yeast would be produced’. The independent variable was the different amount of molasses in the syringe which were 10%, 15% and 25%. The dependent variable for this experiment was the carbon dioxide formation. The control for this experiment was water distilled water with no molasses added Concentration of molasses solution Amount of CO2 produced (ml) Day 1 Amount of CO2 produced (ml) Day 2 10% 2ml 4ml 15% 30ml 40ml 25% 40ml 60ml 0% (control) 0ml 0ml Conclusion My group and I grew yeast in a molasses solution (food for the yeast) and investigated how one factor influences the change in yeast population growth as measured by the amount of carbon dioxide produced. Our hypothesis was ‘If different amounts of molasses were tested for yeast population then the 25% molasses solution would produce the most yeast because the more the amount of molasses then the more yeast would be produced’. My results did agree with my hypothesis, the higher the percentage of the molasses the higher the amount of yeast produced. The 10% made 4ml, 15% made 40ml and 25% made 60ml showed that my hypothesis was right and that because we said 25% would produce the most yeast and it did. We kept the same amount of molasses solution, we kept the same lighting and same temperature (same room), we kept the same amount of yeast in each syringe all the same. Our control in this experiment was that we did add any molasses in the solution and added 1ml of yeast in purified water. Unfortunately we could not conduct this experiment ourselves because during our experiment there was snow storm, spoiling the experiment. So we used data collected by a class that had done it previously . I think we could improve the experiment by actually conducting it ourselves as this would make it more trustworthy. Name: Peter Rene Jarjou