INTRODUCTION
The aim of this experiment was to study the process of alcoholic fermentation in Saccharomyces cerevisiae (yeast cells) and measure the rate of Co2 production during anaerobic breakdown of the respiratory substrate, sucrose, in the yeast cells. The effects of an inhibitor on respiratory enzyme were also looked at. It is hypothesized that the five different reaction mixtures shown in Appendix 1 with their contents, would each have a CO2 production that is not the same. Mixture 1, which was the control, is expected to produce CO2 at a slower rate because it must be converted to glucose first.
There are two ways in which a cell or cells can gain energy – cellular respiration or fermentation. There are two types of fermentation and that is alcoholic fermentation where pyruvate, produced in glycolysis, is converted into lactate, and also lactic fermentation used by plants and some fungi and they convert pyruvate to ethanol and carbon dioxide. Cellular respiration is a fundamental, catabolic process by which food is broken down in order to produce high energy adenosine triphosphate (ATP) molecules. This procedure is carried out by every cell in both plants and animals and is essential for everyday living. There are three main stages to cellular respiration – glycolysis, the citric acid cycle and the electron transport chain.
Glycolysis means “sugar splitting” and takes place within the cytosol of a cell and can continue in both aerobic and anaerobic conditions. Glycolysis is able to produce energy in the absence of oxygen, however, with the presence of oxygen the process is able to have a far more energy efficient oxidative phosphorylation. Glycolysis involves the breaking down of a 6-carbon sugar, glucose, into two smaller 3-carbon sugar molecules of pyruvate (Campbell et al., 2008). Firstly, an ATP molecule is combined with a glucose