"Testing For Organic Compounds" by Devin J

Step 1 for testing for organic compounds you will need to have on the right protection. I suggest to put on goggles ,pants and shoes that cover your feet. Step 2 is to label your five test tubes. Label each test tube with a Crayola number the test tubes 1 through 5. After you label your test tube place them in a test-tube rack. Step 3 is to read your objectives. The objectives is to determine the presence of starch by a chemical test. To analyze solutions for the presence of simple reducing sugars. To analyze a sample of vegetable oil for the presence of lipids. And to analyze a sample of gelatin for the presence of protein. After doing these steps you are all ready to go.
    Part A. We are testing for Complex Carbohydrates (starch). One member of the group used separate droppers for each solution. Another person should be standing out the way from the chemicals reading the person with the droppers what chemical to put in each test tube and how many drops. For test tube 1 add 10 drops of soluble starch. For test tube 2 add 10 drops of glucose solution. For test tube 3 add 10 drops of sucrose. For test tube 4 add 10 drops of gelatin. For test tube 5 add 10 drops of water. Record the color of each test tube's. My groups table data was Starch is white, Glucose is clear, Sucrose is clear, gelatin is light yellow, water is clear. Caution if the iodine is spilled, call your teacher immediately and rinse with water. Water was the control. After we  record the data we add 3 drops of iodine solution to each test tube. Record the data of the color with the iodine. If any of the color change to a dark black its positive of starch. Our data was that starch turned into dark black positive for starch. Glucose was a dark orange negative for starch. Sucrose was a dark orange negative for starch. Gelatin was a dark orange negative for starch. Water was a dark orange negative for starch. Once the group was done recording the data on table 1 we discard the content. We gently brushed the tests tubes in soapy water one by one and then rinse it clean.
    Part B. We are testing for Simple Reducing Sugars. We used a hot plate that was boiling 300 ml of water. My group relabeled the test 1 through 5. Then we got the chemicals we needed. For test tube 1 add 10 drops of soluble starch the color was white. For test tube 2 add 10 drops of glucose solution the color was clear. For test tube 3 add 10 drops of sucrose the color was clear. For test tube 4 add 10 drops of gelatin the color was light yellow. For test tube 5 add 10 drops of water the color was clear. After we recorded the color we added 20drops of benedict's to each test tube. We boiled the chemicals for 3 minutes. Caution not to burn yourself when your getting the test tubes out the water. After the 3 minutes were up we noticed that most of the chemicals were negative for reducing sugar. Starch, sucrose, gelatin, and water were all negative for  reducing sugars. The only positive one was glucose. We recorded our data on table 2. After recording the data we gently brushed the tests tubes in soapy water one by one and then rinse it clean.
    Part C. We are testing for lipids using a brown paper. My group placed a drop of water on a piece of brown paper and circled it and on the top of the circle we wrote water. On a separate spot on the brown paper we placed a drop of oil and circled it and on the top we top of the circle we put oil. We allowed the paper towel to dry for a few minutes. After it was dry we put it in the microwave for 2 minutes. When the 2 minutes were done we held it up to the light. If a semitransparent spot is evident, the sample contains lipids. We recorded the appearance of the two spots in table 3. The water was not transparent and it was negative for lipids. Oil was transparent and was positive for lipids.
    Part D. We are testing for proteins. We made sure we label the test tube 1through 5. Use droppers we add 30 drops of 2% gelatin solution to test tube 1. 30 drops of glucose solution to test tube 2. 30 drops of starch to test tube 3. 30 drops os sucrose to test tube 4. 30 drops of water to test tube 5. We recorded the colors of each test tube in table 4. After recording we add 10 drops of biruet reagent to each test tube. When the reaction does occur ,a violer color appears to indicate the presence of the proteins. Caution biuret reagent is extremely caustic to the skin and clothing. We recorded the colors of each test tube in table 4. Discard the contents of the test tubes. We gently brushed the tests tubes in soapy water one by one and then rinse it clean. We filled in the last column of all five tables with the correct interpretation of the test results. Test tube 1 was violet and positive for protein. Test tube 2 was clear blue and negative for protein. Test tube 3 was cloudy white and negative for protein. Test tube 4 was clear blue and negative for protein. Test tube 5 was clear blue a negative for protein.
    Part E. We were testing for know substance. Put the milk, potato, amino acid, oions, unknow 1, and unknow 2 on a the brown paper. Then put the chemicals in the microwave for 3 minutes. Hold the brown paper to the light to see what kind of molecule it is. Milk is a lipid and a simple sugar. Potato isn't a lipid, it has starch, protein, my teacher added something to make it a starch. Amino acid isn't a lipid, and is a protein. Onion isn't a lipid, it has carbohydrate, sugar ,and starch. Unknow 1 didn't have lipids, had starch, and proteins. Unkow 2 didn't have lipids, and it had starch.
    I think the purpose of the lab is to test for organic compounds. This lab help me get a better understanding of starch. Starch is a polysaccharide (a coiled polymer of glucose) that can be detected in a substance by using the indicator iodine. When iodine is applied to starch, it reacts with the coiled polymer and turns from brownish yellow to bluish black. Another polysaccharide is glycogen that is found in animals. When iodine is applied to glycogen it produces an intermediate color reaction. I also didn't know that metabolism is the sum total of all of the chemical reactions in your body. The metabolism includes catabolic reaction (compound building) and anabolic reactions (compounds breaking). This lab is going to be helpful when I want to test for complex carbohydrates, simple reducing sugars, lipids, and proteins.