ANAEROBIC RESPIRATION: THE EFFECT OF pH ON THE RATE OF FERMENTATION IN YEAST
Andrew Weaver
3/22/13
BYS 119-3L
Lab Partner: Brandon Laue
Introduction
The results of an experiment to determine how pH affects the fermentation rate of yeast will be discussed in this lab report. The fermentation test is simple: anaerobic respiration yields carbon dioxide, so to measure the rate at which yeast is fermenting, one can measured the amount of carbon dioxide gas that is trapped in the Smith fermentation tube. This is directly correlated to how quickly the yeast is fermenting (Stallsmith 2011).
To investigate how rapidly yeast ferments, one needs to learn about fermentation. Fermentation is the breakdown of glucose into energy, without the presence of oxygen. The first cells are believed to have developed in a world without oxygen, making it necessary for them to produce ATP, or energy, anaerobically. Without anaerobic respiration, cells would not have been able to metabolize the sugars they produced into energy; therefore no energy could carry out other cellular activities and processes. Cells later developed the ability to use atmospheric oxygen to break down glucose. All cells today still maintain the ability to perform anaerobic respiration (Stallsmith, 2011). When it performs anaerobic respiration, the yeast produces carbon dioxide and breaks down the glucose in the solution with and coverts the enzymes in the glucose molecule into carbon dioxide, ethyl alcohol, and ATP. ATP (adenosine triphosphate) is a molecule that is used to store energy in organisms that use a metabolic processes (Brilliant Biology Student 2012). Respiration is dependent upon various factors in the environment. Temperature and in some cases salinity can alter or halt the rate of either aerobic or anaerobic respiration in a cell (Campbell 2011).
The pH can affect the rate of respiration. In this experiment, the pH’s effect on yeast are investigated. To determine the affect of the pH,...