Introduction - Research Question: How does the change in pH affect the fermentation of yeast and its effect on the product ethanol? Yeast: Yeast are unicellular microscopic organisms that are able to by budding and are used to convert sugars into alcohol and carbon dioxide. It is a member of the kingdom of fungi where currently there are over 1500 different species and strains of yeast. Yeast can be found almost anywhere, whether it is animals plants or soil. The cellular structure of yeast is that of a eukaryotic cell as yeast cell contains a nucleus. Although its unicellular in nature it posses a cellular organization of that of a multi-cellular. This allows it to replicate faster and making it generally easily to manipulate it genetically. There are many applications for the use of yeast such as food supplements, brewery and biofuels. However in this essay we will focus more on the application of biofuels through the conversion of sugar to alcohol, otherwise known as fermentation. The understanding of fermentation first came into light in 1789 by a french chemist known as Antoine Lavosier, who studied the transformation of substances. Through quantitive chemistry, he studied the mechanism of fermentation by estimating the general proportions of sugar and water molecules in sugarcanes with the with the end products such as carbon dioxide and ethanol; he also added yeast. In his conclusion, two thirds of the sugar was reduced into ethanol and the other one third was