To make a double helix model of DNA out of candy, use toothpicks and colored marshmallows to create the base pairs and attach them to licorice strands to create the sugar and phosphate backbone. Once the model is constructed, twist both ends in opposite directions to resemble the double helix model.
Strands of DNA in a double helix are composed of the four chemical bases of adenine, guanine, cytosine and thymine. The bases pair together, adenine with thymine and cytosine with guanine, and connect to a phosphate molecule and a sugar molecule to form the strand. When formed, the paired bases resemble the rungs of a ladder while the phosphate and sugar molecules act as the vertical sidepieces.
- Assemble candy
- Pair the bases
- Create a ladder
Put the candy pieces together using two pieces of licorice as the phosphate and sugar molecules, and then use four different colors of marshmallows as the chemical bases.
Assign names to the different colors of marshmallows, and pair the adenine pieces with thymine pieces and the cytosine with guanine pieces. Use a toothpick to hold the marshmallows together.
Once the bases are paired, attach either end of the toothpick to the two licorice pieces along the length of the licorice until the model resembles a ladder. Once all the rungs are in place, pick up the model and twist the top and bottom in opposite directions to resemble the double helix.