Who took Jerell's iPod?

9/12/13

    In the last Honors Biology class, Wednesday September 11th, we started out by showing our knowledge of macromolecules. We learned about Carbohydrates, Proteins, and Nucleic Acids for homework the previous night.

Nice picture of cell structure.

Another thing that we leaned included the synthesis and breakdown of polymers, known respectively as dehydration and hydrolysis. There were tons of other things regarding macromolecules that we learned, but it would take forever to go into detail of each one.

     After the macromolecule review, we begun our Organic Compounds Lab. There were two experiments to choose from, and Brian and I chose to do the mystery lab, which was titled Who Took Jerell's iPod? What we did first was test Vegetable Oil, Glucose, Starch (either from corn or potatoes), and Powdered Eggs for Glucose, Starch, Proteins, and Lipids. The Benedict's and the Iodine test came out as expected, with the with the Benedict's(glucose tester) turning orange for the Glucose, and the Iodine(tests for starch) turning a mixture of dark blue, indigo, and black upon contact with the Starch. For the other two tests, we got some results that seemed a little obvious as well. The Bluret, which tests for Protein, came back positive for the Powdered Eggs, turning a lavender color. For the Sudan III, a lipid tester, we got positive results for the Vegetable Oil.

     The two tests pictured below were used for testing Glucose and Lipid. The first test shown below is the Benedict's test, and this shows if Glucose is present. If there is Glucose present, it will turn an orange color as seen in the second picture below. The other test, image 3, is a paper bag test, which tests for the Lipids. We ended up abandoning the paper bag test however, and changed to a must faster Sudan III test, that also tested for Lipids.

Benedict's test at the start.

Benedict's test after a few seconds.

Abandoned paper bag test for lipids.

     The Bluret (Protein Tester) and the Sudan III (Lipid Tester) results are shown below in this picture.

The Bluret test positive for Powdered Eggs, the lavender bottom and third from the left
The Sudan III test positive for Vegetable Oil, the bright red one in the middle left. 

     Next, we did the same four tests on Pretzel crumbs, Butter, Jelly, Fat-free yogurt, and Beans. For the  Benedict's test (Glucose), we got that Jelly tested positive. For the Iodine test (Starch), we got that Pretzels and Beans tested positive. For the Bluret test (Protein), we got that the Fat-Free Yogurt tested positive. And for the Sudan III test (Lipids/Fats), we got that Butter and Beans tested positive. The Buret and Sudan III tests can be seen for all five samples in the picture below.

     The last two things that we tested were a dry part of Jerell's evidence, and a liquid part of Jerell's evidence. After doing all four tests, we determined that the liquid sample came back negative for everything, but the dry sample tested positive on the Iodine test, turning black. This means that there was Starch present in the dry food sample of the person who stole Jurell's iPod.

     Since the Pretzel and the dry sample both tested the same in all three tests, it can be inferred that the thief was eating a Pretzel for lunch. The only person who had a Pretzel during lunch was Kiara, so it must have been Kiara who stole Jerell's iPod. Case closed.