Organic Macromolecules Found In Food

After Mrs. Reifke of Chula Vista High School.

Question

What organic macromolecules are found in common foods?

Generic Test Method - used for all our tests

Procedure for generating controls

  1. You and your group will proceed to a work station to create our controls.
  2. At the work station, use the Generic Test Methods above create the controls and to complete Table 2.
  3. Substitute the "Unknown" shown in Table 2 for the unknown of the Generic Test Methods.
  4. Make sure to place the control substances in the properly labeled test tubes.
  5. Once all of the control tests have been performed, leave the results at the station!

Procedure for testing foods

  1. The second part of the lab will involve your group rotating to other work stations.
  2. Each station has one or two containers with food.
  3. For each food, perform all of the Generic Test Methods described above.
  4. Compare any changes in the color of the solution or the appearance of the paper.
  5. If a food tests positive for a given macromolecule, record a “+” in Table 3.
  6. If a food tests negative for a given macromolecule, record a ““ in Table 3.
  7. All four tests will be done on the foods before moving on.
  8. The three test tubes must be cleaned before changing stations.
  9. Do not clean the control test tubes!
  10. Rotate when told to, but do not move before you are instructed to do so.
  11. You will eventually complete all stations. Work quickly but carefully.
 
Name:

Table 1. Your predictions about macromolecules found in common foods. +/–

Food Monosaccharide Polysaccharide Protein Lipid
Milk        
Applesauce        
Oatmeal        
Soda        
Turkey with gravy        
Macaroni and cheese        
Egg White        
Unknown Substance        

Table 2. Indicators and the macromolecules they test for.

Macromolecule "Unknown" Indicator Initial State of Indicator Final State of Indicator
Monosaccharide Sugar      
Polysaccharide Starch      
Protein Albumen      
Lipid Vegetable Oil      

Table 3. Macromolecules found in various foods. +/–

Food Monosaccharide Polysaccharide Protein Lipid
Milk        
Applesauce        
Oatmeal        
Soda        
Turkey with gravy        
Macaroni and cheese        
Egg White        
Unknown Substance        

Questions

  1. What are the four organic macromolecules found in foods that were tested for in this lab?
  2. What foods were tested in this lab?
  3. Identify a chemical or other substance that can be used to indicate the presence of each of the following macromolecules: monosaccharides, polysaccharides, proteins, and lipids.
  4. For each of the macromolecules in question #1, identify at least one type of food that contains that substance.
  5. What nutrients were found in each of the foods tested?
  6. For which foods was the hypothesis completely supported?
  7. For which foods was the hypothesis NOT supported?
  8. Explain at least 3 possible sources of experimental error. Be specific.
 

Teacher Notes

Materials