Effect of Different Isomers of Sugar on Yeast Respiration |
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Author(s): Tom Schuster, Rosalie Van Zyl, & Harold Coller | Longitudinal Study
SED 695B; Fall 2005 |
Research Question: |
A Possible Setup |
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Standards addressed: Biology/Life Sciences Investigation and Experimentation |
Independent variable |
Dependent variables |
Controls |
Series |
Time (minutes) |
Carbon Dioxide Production |
Sugar concentration Yeast Water Temperature |
Monosaccharides: Dextrose (Glucose) Levulose (Fructose) Galactose Disaccharides: Sucrose Maltose Lactose |
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Procedures:
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Materials: |
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Labware:
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Consumables:
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Sugars are simple carbohydrates. Also called saccharides, the come in two forms: monosaccharides and disaccharides. Monosaccharides have the chemical formula |
This table shows the data collected every 5 minutes until no more gas could be collected. | |
Clearly, maltose is the best for yeast metabolism. Remember, yeast is made of two glucose molecules. Glucose (aka dextrose) is a close second. Fructose is in third place. Interestingly, sucrose, made of glucose and fructose, does not perform well. Perhaps yeast do not have an enzyme to access sucrose's energy. Fructose, galactose, and lactose produced very little, if any cellular respiration in yeast. | |
It is interesting to note that, not only do these sugars look different, but they also have distinct odors. |
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Each gram of yeast contains about 1 billion cells. That's 1,000,000,000 cells! | |
References & Links: General info on yeast
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