Design Your Own DNA Molecule
Supplies Needed (per model)*
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2 white 12” chenille stems (aka “pipecleaners”)
2 colored 12” chenille stems
12 aqua 6mm (pony) beads (A)
12 purple 6mm beads (G)
6 red 6mm beads (T)
6 yellow 6mm beads (C)
scissors
ruler
*NOTE: You may use different colors of beads than what is specified. Packages of 100
chenille stems cost approx. $1.50; Packages of 300 pony beads cost approx. $1.50; An
entire classroom set can be purchased for under $10
Directions:
1. Cut each white chenille stem into six 2 inch sections.
2. The pony beads represent the 4 different bases:
Adenine (A) - aqua
Thymine (T) - red
Guanine (G) - purple
Cytosine (C) – yellow
3. Because A and G molecules have 2 rings, you will use 2 beads for each of these molecules. Use one
bead for T and C molecules, which have only one ring.
4. Thread beads representing an Adenine and Thymine base pair onto one of the 2-inch white chenille
stems. (Remember to use 2 beads for A and one bead for T). Prepare 6 of these segments.
5. Prepare 6 Guanine and Cytosine base pairs, using 2 purple beads for G and 1 yellow bead for C.
6. Connect one white chenille segment to the colored chenille stem approx. 1 cm from the top. Wrap the
end of the white stem around the colored stem. Connect the other end to the second colored chenille
stem (see photo). This is where you can be creative with the genetic code - you can choose to make
your own DNA sequence!
7. Follow the same procedure for the remaining white segments and beads. Add each consecutive base
pair (white chenille segment) approximately 1 cm from the previous base pair.
8. When all 12 base pair segments have been added to the DNA molecule, you should have a molecule that
looks like a ladder.
9. To make your double helix, twist your model slightly so the molecule forms a spiral. DNA molecules have
a right-handed helix shape that winds in one direction (see diagram on next page). You can figure out the
direction by sliding the fingers of your right hand along backbone. If it is right-handed, your thumb should
be moving forward while you do this.
10. CONGRATULATIONS! You have created your own unique DNA molecule. The sequence of the base
pairs in the DNA ladder is what makes different DNA molecules unique, and is what the Human Genome
Project and other genome sequencing projects are all about. Compare your DNA molecule with other
DNA molecules. How are they similar? How are they different?
Carolyn A. Zanta, UIUC-Hughes Biotechnology Education and Outreach Program (www.life.uiuc.edu/hughes/footlocker)
Background Information: DNA
DNA = Deoxyribonucleic Acid
DNA is made of nucleotides
Nucleotides contain a base (A, T, G, or C) +
deoxyribose sugar + phosphate
The 4 different bases form base pairs:
Adenine binds with Thymine
Guanine binds with Cytosine
The shape of DNA is a double helix with a
right-handed spiral turn (like a twisted ladder)
with the steps representing the base pairs and
the sugar+phosphate backbone as the hand
rails. In our model, the colored chenille stems
represent the phosphate (P) groups and the
white portion that wraps around the colored
stems represents the sugar groups (S) (see
diagram below).
Figure from Access Excellence (www.accessexcellence.org)
DNA model with a right-handed helix
Carolyn A. Zanta, UIUC-Hughes Biotechnology Education and Outreach Program (www.life.uiuc.edu/hughes/footlocker)