Download Build Your DNA and Eat It Too

Build Your DNA and Eat It Too
Objective:
1. Students will be able to describe the structure of the DNA molecule.
2. Students will be able to explain the rules of base pairing.
3. Students will understand that information is stored within the DNA molecule in
the form of a sequence of chemical bases, each referred to by the first letter of its
name (A, T, C and G).
Safety:
Students will be using sharp objects including a needle and scissors.
Materials:
 Red and black licorice sticks
 Colored marshmallows or gummy bears
 Toothpicks
 Needle
 String., Fishing line, or fine thread
 Scissors
Hypothesis: N/A
Procedure:
1. Gather together red and black licorice sticks, colored marshmallows or gummy
bears, toothpicks, needle, string, and scissors.
2. Assign names to the colored marshmallows or gummy bears to represent
nucleotide bases. There should be four different colors each representing either,
adenine = pink, cytosine = yellow, guanine = green or thymine = orange.
3. Assign names to the colored licorice pieces with one color representing the
pentose sugar molecule and the other representing the phosphate molecule. Black
= phosphate and Red = deoxyribose.
4. Use the scissors to cut the licorice into 1 inch pieces.
5. Using the needle, string half of the licorice pieces together lengthwise alternates
between the black and red pieces.
6. Repeat the procedure for the remaining licorice pieces to create a total of two
stands of equal length.
7. Choose one of the sequences below.
Sequence 1: T A C G T A T G A A A C
-or Sequence 2: T G G T T T A G A A T T
8. Connect two different colored marshmallows or gummy bears together using the
toothpicks.
9. Connect the toothpicks with the candy to the red licorice segments following the
sequence 1 or 2.
10. Holding the ends of the licorice sticks, twist the structure slightly.
11. Label the backbone. With a marker or pen and masking tape, label your licorice
12. backbone “DNA- 1” or “DNA-2” depending on which sequence you used. Write
the label on the left end of the licorice.
13. Label your model. Make flags to label the parts of your DNA out of paper clips
and tape. Label one of each of the following: adenine, thymine, cytosine,
guanine, and the backbone – the phosphate and the deoxyribose.
Analysis:
1. How do the bases pair up in a DNA molecule? How does your model help you
figure this out?
2. What differentiates one DNA molecule from another? How could you change
your DNA model to reflect changes among DNA molecules?
Conclusion:
1. How do you think a DNA molecule makes an exact copy of itself? How does its
structure help it do so?