How to Make DNA Models

Make your own DNA model with household items.

DNA (Deoxyribonucleic acid) is a nucleic acid, or large molecule, that contains the genetic code or blueprint used in the creation of all living organisms and some viruses. DNA pieces are called genes. DNA comprises two long polymer strands called nucleotides, each with a backbone of sugars and phosphates. The backbone sugars are joined to rungs of two of four molecules called bases, which pair up as adenine and thymine, and guanine and cytosine. It is this sequence of four bases that actually encodes genetic information. Making DNA models is simple and can be done with household items.

Things You'll Need

• 2 white 12-inch pipe cleaners
• 2 purple 12-inch pipe cleaners
• 12 blue 6mm beads
• 12 green 6mm beads
• 6 red 6mm beads
• 6 yellow 6mm beads
• Scissors
• Ruler

Instructions

1. Cut two white pipe cleaners into 2-inch segments. This should make 12 small pieces of pipe cleaners. These represent the rungs that bond the bases to the DNA backbone sugars. DNA has billions of rungs, so you can only create one small piece of DNA.

2. Sort the beads by color for each of the four bases. Adenine is blue, thymine is red, guanine is green and cytosine is yellow. Any colors may be used, as long as there are enough beads in four colors.

3. Arrange the beads into their base pairs. Adenine (blue) pairs with thymine (red), and guanine (green) pairs with cytosine (yellow). Adenine and guanine molecules have two rings each, so they need two beads, compared to thymine and cytosine, which need one bead each. For the adenine and thymine pair, sort their beads into groups of two blue and one red. For the guanine and cytosine pair, sort their beads into groups of two green and one yellow. Keep the beads of the two-bead bases next to each other. There should be 12 sets of three beads.

4. Create the base pair rungs. Push each 2-inch white pipe cleaner through a set of three beads that were grouped in Step 3. Leave a 1/2-inch piece of white pipe cleaner free on both sides of the beads. The ends will attach to the backbone in the next step.

5. Attach each rung to the backbone. Take each white, beaded pipe cleaner and wrap each end around one long purple pipe cleaner. Begin 3/4 inch from the end of the purple pipe cleaners and attach a white rung at each 3/4-inch interval. It will resemble a ladder. The order of the pairings does not matter, so they can be mixed randomly.

6. Create the right-handed double helix. Starting from the bottom of the pipe cleaner ladder, turn it to the right in a spiral all of the way up until you reach the top of the ladder.