How to Make a Homemade DNA Model

DNA, or deoxyribonucleic acid, is present in the nucleus of a cell. It is a chemical that dictates how cells are built. Genes are segments of DNA. A strand of DNA is called a double helix. It looks like a twisted ladder. The rails of the DNA are composed of phosphoric acid and deoxyribose. The rungs are composed of organic bases---Adenine, Thymine, Cytosine and Guanine. There are two bases present on each rung. Adenine and Thymine are always paired and Cytosine and Guanine always coupled.

Things You'll Need

• Hollow red and black licorice sticks
• String
• Gummy bears
• Toothpicks
• Miniature marshmallows

Instructions

1. Slice the hollow licorice sticks into 1-inch pieces. You will need red and black licorice. These pieces will be used to make the rails of the ladder.

2. Tie a knot in the bottom of a piece of string. Place the pieces of licorice on the string, alternating red and black pieces. Repeat to make a second string of equal length. The stringed pieces represent the phosphoric acid and deoxyribose rails.

3. Place the gummy bears on toothpicks. Separate four different colors of bears. Choose two colors. Place a miniature marshmallow in the middle of a toothpick. Place a different color gummy bear on each side of the miniature marshmallow.

4. Place the other two colors of gummy bears around a miniature marshmallow on a toothpick. Repeat this step until you have enough to insert one toothpick into each red piece of licorice on the string. Always use the same two colors of gummy bears together on the toothpicks. The toothpicks will be used to make the rungs of the ladder.

5. Attach the toothpicks to the licorice strands. Insert the end of a toothpick into the first red pieces of licorice on each strand. Insert a toothpick with different colored gummy bears on the next red piece. Continue until you have inserted toothpicks in all red pieces of licorice.

6. Twist the ladder. Grasp the top and turn counterclockwise to give it the shape of the double helix. Your DNA model is now complete.

Tips & Warnings

• The red licorice pieces symbolize deoxyribose. The black licorice symbolizes phosphoric acid. The miniature marshmallows symbolize the hydrogen bonds between the four bases---Adenine, Thymine, Guanine and Cytosine. The bases are represented by the four colors of gummy bears.

• DNA strands separate at the hydrogen bonds during duplication. The new strand of DNA will attach to the originating hydrogen bond.

References

• Discoveryeducation.com: Building a Model DNA
• Dnamazing.com: Make a Model DNA Strand
• Hometrainingtools.com: Build a DNA Model