An organic molecule is a molecule that is normally in or produced by a living system. These molecules typically consist of carbon atoms in rings or long chains that allows other atoms such as hydrogen, oxygen and nitrogen to attach. The organic compounds are grouped into four major categories known as carbohydrates, lipids, proteins and nucleic acids (Reece, Urry, M.Cain, & et al, 2014). This lab was designed to chemically distinguish between the four groups and apply the results to an unknown solution and food of a potato, onion and bacon fat. Carbohydrates include sugars and polymers of sugars. Carbs can be disaccharides when double sugars consisting of two monosaccharaides are joined with a covalent bond. Polysaccharides are polymers with a few hundred monosaccharaides joined by glycosidic links. A potato is a storage polysaccharide. Plants store starch allowing them to have an abundance of glucose for energy (Reece, J., Urry, L., M.Cain, & et al, 2014). To test for carbohydrates a Benedict Test would need to be performed. This test is important for testing monosaccharides or simple sugars such as glucose and fructose. Benedict's reagent contains blue Cu+2; when these are combined in the presence of an aldehyde group an oxidation reaction occurs resulting in the formation of carboxylic acid plus a red insoluble precipitate CuO (Hughes, 2009). Sugars that can be oxidized are called reducing sugars. To test for a starch and glycogen or poloysaccharide, a Lugol's Test should be performed (Shanholtzer, pp B1-6, 2014). Lugol's Test (I2KI) is used to determine the presence of starch in a compound. The iodine targets the short amylose coil attached to the starch and turns it into blue-blackish color. If amylose is not present, then the color change is not visible (Ophardt, 2003). .
Lipids are the one class of biological molecules that do not contain true polymers. Lipids are also hydrophobic and mix very poorly if at all with water.