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 both cases, carbon dioxide, CO2, is produced. The rate that this gas is produced is referred to as the rate of respiration.
In the Preliminary Activity, you will use a CO2 Gas Sensor to determine the rate of respiration of glucose by yeast.
After completing the Preliminary Activity, you will first use reference sources to find out more about sugars, respiration, and yeast before you choose and investigate a researchable question dealing with the respiration of sugars by yeast. Some topics to consider in your reference search are:
- aerobic respiration
- anaerobic respiration