Classification of Macromolecules

2186 Words Apr 6th, 2009 9 Pages
ABSTRACTThe purpose of this lab was to determine if various substances contained macromolecules, specifically; carbohydrates, proteins, or vitamin C. The tests used were the Biuret test, the xanthoproteic test, the Benedict's test, the starch test, and the indophenol test. Many of the substances were positive for that which they were being tested, proving the hypothesis partially correct.

INTRODUCTIONThis lab was conducted to determine if various substances contained various macromolecules. The macromolecules tested for were carbohydrates, proteins, and vitamin C. The substances tested were glucose, fructose, sucrose, maltose, milk, corn syrup, starch, glycogen, gelatin, egg albumin, ascorbic acid, apple juice, orange juice, and fruit
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Elementally, proteins are made up of hydrogen, oxygen, carbon, and nitrogen. Smaller chains, of only a few amino acids, are called peptides rather than proteins. Gelatin, egg albumin, and milk were the substances tested for proteins. The Benedict's test tested for the presence of peptide bonds, whereas the xanthoproteic test tested for a benzene ring. Peptide bonds are found in all proteins, while benzene rings are not. (Campbell, 2004) (Malyk, 2007c) (Reusch, 2007b)The last macromolecule tested for was vitamin C. Vitamin C is an acid, which is produced from glucose or gathered from nature. Being a vitamin, it is essential to animals but cannot be synthesized by the animal. It plays a crucial role in the production or collagen, helps wound healing, and helps boost the immune system. It is found naturally in foods like citrus fruits, cabbage and tomatoes. Vitamin C is made up entirely of hydrogen, carbon and oxygen, and has the chemical formula of C6H8O6. Vitamin C is best taken from raw foods due to the fact that the chemical structure can easily be changed by heat or air exposure. To test for vitamin C, it will be titrated with a known volume of indophenol. When equilibrium is achieved, indicated by a color change to pink or colorless, the test is considered positive. Ascorbic acid, orange juice, apple juice, and fruit punch were tested for vitamin C. (Malyk, 2007d)
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