Nucleic Acids
Chemicals of Life
1. Problem: What macromolecules are found in a ham sandwich?
2. Hypothesis: Hypothesize which macromolecules you expect to find in the ham sandwich
ingredients you’ll test today. “If a macromolecule test is ran on a ham sandwich, the
macromolecules that will be found are ……………….”
3. Materials: Station 4: Testing for Nucleic Acids
Microcentrifuge tube containing Unknown A
Microcentrifuge tube containing Unknown B
Microcentrifuge tube containing Unknown C
Microcentrifuge tube containing Unknown D
Microcentrifuge tube containing Unknown E
Beaker containing diphenylamine
solution
10 Microcentrifuge tubes and tray
Pipets
Beakers with samples of ham, lettuce,
cheese and bread
Safety Precautions: Diphenylamine is moderately toxic by ingestion. Wear chemical splash
goggles.
4. Procedure:
Part 1: In Part 1, you will perform a test on each unknown to learn what a positive test for
nucleic acids looks like.
1. Make sure your Microcentrifuge tray had ten, clean, labeled Microcentrifuge tubes
in it (labeled A, B, C, D, E, ham, cheese, lettuce, bread, and water).
2. Add 6 drops of Unknown A to Tube A. Add 6 drops of Unknown B to Tube B, etc.,
through E.
3. Add 24 drops of diphenylamine solution to each Tube (A-E).
4. The solution will turn purple in color if DNA is present and green if RNA is present.
5. Record any positive results with a + in the data table.
Part 2: Now you will use the same test on ham sandwich ingredients to determine what
macromolecules are found in a ham sandwich.
1. Put 6 drops the following per tube: ham, cheese, lettuce, bread, or water.
2. Add 24 drops of diphenylamine solution to each tube.
3. Record any positive results with a + in the data table.
5. Data/Observations:
Unknown
Carbohydrate
A
B
C
D
E
Protein
Lipid
Nucleic Acid
Ham
Cheese
Lettuce
Bread
Water
Results: Answer the following questions in complete sentences. (Restate the question in
your answer.)
1. Which unknowns contained carbohydrates? Which unknowns contained proteins?
Lipids? Nucleic acids?
2. Which ingredients of the ham sandwich contained carbohydrates? Which
ingredients contained proteins? Lipids? Nucleic Acids?
3. How did you know the answer to #2? (In other word, what evidence do you have that
the ham sandwich contained carbohydrates, etc.?)
6. Conclusion:
1.In a paragraph, answer the following:
 What macromolecules did you find in a ham sandwich?
 Was your hypothesis correct or not? Give evidence from your results to back up
your answer.
 What errors could have occurred to make your testing inaccurate?
 How would you improve the experiment (what would you do differently next time) or
how could you extend the experiment further?
2. What part(s) of the ham sandwich are or were once composed of cells? Defend your
answer from the experiment.