Today, we tested the monomers of the macro-molecule carbohydrates . The monomers of carbs are sugars, or monosaccharides. We tested common sugars and measured their degrees of sweetness to see what the difference between each monomer was. The monomers we tested were : glucose, fructose, galactose, lactose, maltose, sucrose, starch, and cellulose. Glucose, fructose, and galactose are classified as monosaccharides, meaning that they only have one ring. Maltose, and lactose were disaccharides, meaning that they have two rings. Starch and cellulose are polysaccharides, so they were composed of many rings. We noticed an inverse relationship between the number of rings that each monomer had and the degree of sweetness that we measured. For example, we rated fructose as having a 100 degree of sweetness, while starch and cellulose each got a 0. So we concluded that as the number of rings went up, the degree of sweetness went down.
As the lab continued, we found it easy to relate these carbohydrates to foods that we had eaten before. Fructose tasted similar to honey, since it was really sweet. Cellulose, on the other hand, reminded us of paper, which made sense when we learned that cellulose is a main component of paper. Starch vaguely reminded us of vegetables, which also was a expected since starch is produced by many green plants.
After the lab, we decided to to an extension to see how humans tasted sweetness. According to NPR, the taste buds have about 50-100 taste cells on the outer tips of the bud, and a different percentage of buds taste sweetness, while other percentages taste salty, sour, bitter etc.. There are proteins on the tongue specifically for tasting sweetness, and a chemical reaction takes place when the sugar or sweetener encounters the protein. It sends a signal to the brain, and different parts of the central nervous system respond to the sweetness.
Source: "Getting a Sense of How We Taste Sweetness." NPR. NPR, 11 Mar. 2011. Web. 29 Aug. 2015.
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