Macromolecules Analysis Lab Chemistry of Life Macromolecules Analysis Lab

Starter Name the six elements all living things are made of. Name the monomers of the 4 macromolecules. What is the property of water that is responsible for capillary action?

Carbohydrates Sugar Test Benedict's Solution is used to test for simple sugars, such as glucose. It is a clear blue solution.

Carbohydrates In the presence of simple sugars, the blue solution changes color to green, yellow, and red, depending on the amount of sugar.

Carbohydrates Procedure In a beaker mix a small amount of the food sample with distilled water to make a test liquid. To a test tube, add 40 drops of liquid to be tested. Add 10 drops of Benedict's solution to each test tube. Carefully heat the test tubes by suspending in a hot water bath at about 40-50 degrees Celsius for five minutes. Note any color change. If sugar is present solution will turn green, yellow, or brick-red, depending on sugar concentration.

Carbohydrates Starch Test Iodine Solution is used to test for starch. IKI is a yellow solution.

Procedure Carbohydrates Place a small amount of the food sample in a beaker. Add 5 drops of iodine solution on the sample.

Carbohydrates Starch Test Look for a dark blue-black color to appear. A dark color indicates the presence of starch.

Lipids Brown Paper Test is used to test for lipids. Certain kinds of paper such as a piece of brown paper bag can readily absorb lipids and can be used to test for the presence of lipids.

Lipids Procedure Draw a circle on a brown paper bag. Place a drop of the sample on the brown bag. Allow the paper to dry for 15 minutes. Remove any sample that has not been absorbed. Turn the paper to the opposite side to review your results. You will see a stain (oil) for a positive result.

Proteins Biuret Solution is used to identify the presence of proteins. Biuret reagent is a blue solution.

Proteins Procedure Mix small amount of each food sample with distilled water to make a test liquid. To a test tube, add 40 drops of liquid to be tested. Add 3 drops of Biuret reagent solution to the test tube. Shake gently to mix.

Note any color change. Proteins will turn the solution pink or purple.

Indicator Macromolecule Negative Test Positive Test Benedict’s Solution Simple Carbohydrate Blue Orange Iodine Solution Complex Carbohydrate Dark Red Black Biuret Solution Protein Violet/black Paper Bag Lipid No Circle Oil Circle