Enzyme Lab Report

Topics: Purple, Blue, Glucose Pages: 5 (1802 words) Published: December 12, 2011
Danny Fish

Chemical Testing To identify An Unknown

The hypothesis tested was that depending on the solution presented, which would test positive for one of the following, proteins, carbohydrates, or lipids through use of chemical testing. (Sudan IV, Benedicts’ Solution, Iodine, Biuret’s) . In order to gain more information for the hypothesis, one must know how to test for said macromolecule. Each of the above stated molecules has their own individual solution that will in turn identify which molecule is present. The corresponding test are as followed; Sudan IV is used for testing for lipids, if in fact a lipid is present, the reaction would produce a red/orange color as opposed to no change at all (negative reaction: Stays pink color). This solution of Sudan IV is soluble in lipids, but not in water. Benedict’s solution is the test used for reducing sugars or glucose testing. The positive reaction for this test should show a red/brick color after being placed in boiling water for three minutes, but if a negative reaction occurs we will get blue color or no change at all. Another test that we were introduced to was the iodine test, which is used to detect starch. A positive reaction would result in a blue/black color, where as a negative reaction would be an amber color. Then in order to find the remaining agents (peptide bonds) we used Biuret’s solution, a violet color is produced when there is a positive reaction. Where as a light blue color is produced in the negative reaction.

The overall goal of this experiment is to find three of the four macromolecules (proteins, lipids, carbohydrates) that you can find in everyday living organism. These macromolecules are the chain like proteins, carbohydrates, and nucleic acid. These macromolecules are made of smaller units that are called monomers that make up polymers of covalently boding the identical and/ or similar monomer building blocks. These monomers are repeating units serving as building blocks for the polymers. The macromolecules need these smaller units to help complete their own tasks. These monomers form the common polymers carbohydrates, lipids, and proteins. Carbohydrates and lipids provide energy and storage, where proteins act as transportation and the storage cells. The negative and positive controls of the experiment would be that, if the solution changes color the hypothesis above would be correct, while if it has no change then the null hypothesis would be true. The overall goal of this experiment was to discover the unknown molecule, with chemical testing. If the colors changes during the reaction then we would have a positive test in regards to the macromolecule that we are testing for.

For the benedicts reducing sugars test, we obtained two groups of eight test tubes and numbered each set one threw eight. For group one the Benedict’s reducing sugars, we placed ten drops of onion juice test tube one along with 2mL of the Benedicts solution, test tube two is then filled with ten drops of potato juice and 2mL of benedicts solution, test tube three is filled with ten drops of sucrose solution followed by the additional 2mL of the benedicts solution, Test tube four is filled with ten drops of the glucose solution followed by an added 2mL of Benedicts solution, Test tube five is then filled with ten drops of distilled water with the benedicts solution (2mL), test tube six is then filled with the reducing sugars solution ten drops as well along with the benedicts solution, tube seven will be for the ten drops of starch solution followed by the 2mL of benedicts solution, then for test tube eight this will be your unknown, there will be 2mL of the unknown and 2ml of the benedicts solution mixed in tube eight. Then proceeded to place the eight test tubes into boiling water where they sat for 3 minuets, while we looked to see if there had been any color change.

For the Iodine test for Starch, the same steps are taken to perform...
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