Chemical Composition of Cells Lab, Lab Reports of Cell Biology

Tests For Organic Compounds

The structures of cells are made up of many different chemical molecules. Most of the common

molecules found in living things belong to four classes of carbon-containing molecules: carbohydrates, lipids,

proteins, and nucleic acids. Cell metabolism involves the production and destruction of many types of

molecules. In order to maintain life, cells metabolize compounds from the foods we eat. Metabolism is the

sum total of all of the chemical reactions in your body. The metabolism includes catabolic reactions (compound

~ To analyze a sample of gelatin for the presenc e of protein.

Materials

vegetable oil test tubes wax marking pencil tap water

glucose solution biuret regent test-tube holder droppers brown paper

soluble starch solu tion Benedict's solution test-tube brush hot plate test-tube stoppers

2% gelatin solution iodine solution test-tube rack 1000 ml beaker goggles and apron

Procedure (Suggestions!! Start a water bath for Part B first...You don’t have to do tests in order)

1. Put on goggles and an apron. Label five test tubes 1, 2, 3, 4 and 5. Place them in a test-tube rack.

2. Using a separate dropper for each solution, add 10 drops of soluble starch solution to test tube 1, 10 drops of

glucose solution to test tube 2, 10 drops of sucrose to test tube 3, 10 drops of gelatin in test tube 4, and 10

drops of water to test tube 5. Record the color of each test tube’s contents in Table 1.

3. Add 3 drops of iodine solution to each test tube. CAUTION: if iodine is spilled, rinse with

water and call your teacher immediately.

4. Record in Table 1 the color of each test tube’s contents after addition of the iodine.