Vernier Software & Technology

# Sugar Fermentation

## Introduction

Yeast are able to metabolize some foods, but not others. In order for an organism to make use of a potential source of food, it must be capable of transporting the food into its cells. It must also have the proper enzymes capable of breaking the food’s chemical bonds in a useful way. Sugars are vital to all living organisms. Yeast are capable of using some, but not all sugars as a food source. Yeast can metabolize sugar in two ways, aerobically, with the aid of oxygen, or anaerobically, without oxygen.

In this lab, you will try to determine whether yeast are capable of metabolizing a variety of sugars. Although the aerobic fermentation of sugars is much more efficient, in this experiment we will have yeast ferment the sugars anaerobically. When the yeast respire aerobically, oxygen gas is consumed at the same rate that CO2 is produced—there would be no change in the gas pressure in the test tube. When yeast ferment the sugars anaerobically, however, CO2 production will cause a change in the pressure of a closed test tube, since no oxygen is being consumed. We can use this pressure change to monitor the fermentation rate and metabolic activity of the organism.

The fermentation of glucose can be described by the following equation:

${{\text{C}}_{\text{6}}}{{\text{H}}_{{\text{12}}}}{{\text{O}}_{\text{6}}} \to {\text{2 C}}{{\text{H}}_{\text{3}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{OH + 2 C}}{{\text{O}}_{\text{2}}}{\text{ + energy}}$ ${\text{glucose }} \to {\text{ ethanol + carbon dioxide + energy}}$

Note that alcohol is a byproduct of this fermentation.

## Objectives

In this experiment, you will

• Use a Gas Pressure Sensor to measure the pressure change caused by carbon dioxide released during fermentation.
• Determine the rate of fermentation.
• Determine which sugars yeast can metabolize.

## Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

### Option 2

You may also need an interface and software for data collection. What do I need for data collection?

## Biology with Vernier

See other experiments from the lab book.

 1 Energy in Food 2 Limitations on Cell Size: Surface Area to Volume 3 Acids and Bases 4 Diffusion through Membranes 5 Conducting Solutions 6A Enzyme Action: Testing Catalase Activity 6B Enzyme Action: Testing Catalase Activity 7 Photosynthesis 8 The Effect of Alcohol on Biological Membranes 9 Biological Membranes 10 Transpiration 11A Cell Respiration (O2) 11B Cell Respiration (CO2) 11C Cell Respiration (Pressure) 11D Cell Respiration (CO2 and O2) 12A Respiration of Sugars by Yeast 12B Sugar Fermentation 13 Population Dynamics 14 Interdependence of Plants and Animals 15 Biodiversity and Ecosystems 16A Effect of Temperature on Respiration 16B Effect of Temperature on Fermentation 17 Aerobic Respiration 18 Acid Rain 19 Dissolved Oxygen in Water 20 Watershed Testing 21 Physical Profile of a Lake 22 Osmosis 23A Effect of Temperature on Cold-Blooded Organisms 23B Effect of Temperature on Cold-Blooded Organisms 24A Lactase Action 24B Lactase Action 25 Primary Productivity 26 Control of Human Respiration 27 Heart Rate and Physical Fitness 28 Monitoring EKG 29 Ventilation and Heart Rate 30 Oxygen Gas and Human Respiration 31A Photosynthesis and Respiration (O2) 31B Photosynthesis and Respiration (CO2) 31C Photosynthesis and Respiration (CO2 and O2)

### Experiment 12B from Biology with Vernier Lab Book

#### Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.