Organic Chemistry and Compounds Indicator Tests
Organic Chemistry and Compounds
Indicator Tests for Simple Sugars, Starch, Lipids, and Proteins
AP Biology, Mod 5
Abstract:
The processes of organic chemistry are examined in this experiment through visual qualitative observations. By testing the samples for a particular organic compound (proteins, lipids, or carbohydrates) and simple sugars, the data collected can directly represent the compounds within the solution. Using test tubes filled with either protein, carbohydrate, or lipid rich solutions and an indicator a color change could occur. The results of the tests could be deciphered either positive or negative by the color change or the lack thereof. After the completion of this experiment a better understanding of organic compounds and their respective mediums was achieved.
Introduction:
The labs conducted tested the samples of saltine cracker and lemonade power for all organic compounds including, lipids, carbohydrates, proteins and simple sugars. Each organic compound has a specific role and function in our body. Proteins’ monomers are amino acids. They are enzymes that control many things in the body, such as cell transport, hormone regulation, and much more. (Campbell Biology 43) Carbohydrates’ monomers are monosaccharides. They are the sugars that provide energy. (Campbell Biology 37) Lipids’ monomers are glycerols and fatty acids. They are the fats that store energy. (Campbell Biology 40) The tests were taken to determine what substances were positive for the organic compounds listed above. We designed our own lab so we choose how to test each substance for each organic compound. We hypothesized that if a powdered lemonade solution is tested for proteins, lipids, and carbs, then the test will come back positive for simple sugars through the Benedict’s test, since the lemonade powder had sugar in it. We also hypothesized that if a saltine cracker is tested for proteins, lipids, and carbs, then the test will come back positive for starch through the iodine test.
Methods:
This lab was completed at New Tech High @ Coppell in Mrs. Wootton’s AP Biology class on September 17, 2015. The materials were provided by Mrs. Wootton consisted of 4 test tubes, lemonade powder, crackers, clamps, goggles, 2 petri dishes, indicator solutions (Benedict’s, Lugol’s Iodine, NaOH, CuSo4), and a hot plate. The lab was conducted by first checking the initial results with water and the indicator solutions then by doing the same procedures with the crackers and lemonade. In the lipids test, petri dishes were used to split the crackers and lemonade power. This allowed the group to put oil on one side of the petri dish and water on the other. After completing each test the results were recorded in the table as positive and negative to indicate if the substance contained the compound.
Results:
After completing all the tests and comparing them to tests done on water samples (Which were all negative), the organic compounds in lemonade mixture and crackers were apparent. The lemonade was positive on the simple sugar and lipids test while negative on the starch and proteins test. The crackers were positive on the simple sugar test, the starch test, and the lipids test, while it was negative on the proteins test.
Discussion:
Based on our findings, our hypothesis was tested to be correct. However, some of the test outcomes were still different than what we expected to happen. We hypothesized that the lemonade mixture would come back positive for the simple sugars test, and the crackers would come back positive for the starch test, but we did not know that the crackers also contained simple sugars, and that both tested substances contained lipids.
The test results in this experiment are not completely accurate, since it is solely qualitative data. Color change is used to determine if the test is positive or negative, and deciding what color or shade the result is can vary from person to person. Although the answers are fairly evident most of the time, it still could have or had the potential to skew our findings.
Conclusion:
The purpose of this lab was to understand the different ways to test for all the organic compounds in a substance. Using chemicals like Benedict's and Iodine, we were successfully able to do that, and then determine the organic compounds in more complex structures like food. These testing procedures could be used for countless other experiments to determine the organic compounds for nearly everything.
Works Cited
Reece, J. (2012). Campbell biology: Concepts & connections. San Francisco, CA.: Benjamin Cummings.