How to Make a DNA Model
A DNA model is an interesting way to bring the DNA that dictates the fiber of our being. It can help us understand the physical make-up of DNA and can make for a pretty cool science project. Here are the steps of making your very own DNA model:
What You Need
Small styrofoam balls, around 100 pieces
Wooden laboratory stand
Double-ended toothpicks
Glue
Paintbrushes
Water-based or latex-based paint
Double-Helix DNA Model
Decide the colors you will assign for each of the Nucleotide bases, namely: Adenine, Cytosine, Guanine and Thymine. Keep in mind that these bases are paired to each other. Adenine is paired with Thymine and Cytosine with Guanine. You have the option to make the paired colors complementary. The bases will compose the “rungs” or the steps of the DNA “ladder”.
Choose two colors to represent the Pentose sugar molecule and the Phosphate molecule. They will compose the vertical upright of the DNA “ladder” or the handles.
Separate the styrofoam balls into six groups and color them according to what Nulceotide base they represent. Let them dry overnight. Do NOT use acrylic-based paint as this will melt the styrofoam!
Assemble your laboratory stand.
Make the first row composed of the Cytosine-Guanine pair. Put a bit of glue on the two tips of the toothpics before inserting the Cytosine and Guanine styrofoam balls on each end.
Put in another toothpick on the other side of the Cytosine and Guanine and insert two Pentose styrofoam balls on each end.
Put a toothpick on top of the Pentose styrofoam balls and add the Phosphate styrofoam ball. Put another toothpick on top of the Phosphate styrofoam balls and add the next pair of Pentose styrofoam balls. Remember that the Nucleotide styrofoam bases are only directly attached to the Pentose styrofoam balls.
At this point, you already have the base of the DNA ladder. Secure the first rung of the ladder (made of the Cytosine-Guanine pair with the Phosphate molecule) on the base of the stand using a thin wire. Let the glue dry for a bit to make it more stable.
Make a Adenine-Thymine strand and attach it in the middle of the topmost pair of Pentose styrofoam balls. Add another Phosphate ball on top of the Pentose, and the third pair of Pentose styrofoam balls.
Make a Thymine-Adenine (the colors must have switched places) strand and attach it to the Pentose styrofoam balls.
Make another pair of Cytosine-Guanine (the colors must still be on the same side as the first Cytosine-Guanine pair) and attach it to the Pentose Styrofoam balls.
At this point, you’ve already established the ladder pattern, which can be viewed as such. The first layer is the base of the DNA ladder. Once you reach the seventeenth layer, follow the pattern from the second layer onwards.
Seventeenth layer: Pentose - Cytosine - Guanine - Pentose
Sixteenth layer: Phosphate - - Phosphate
Fifteenth layer: Pentose - Adenine - Thymine - Pentose
Fourteenth layer: Phosphate - Phosphate
Thirteenth layer: Pentose - Guanine - Cytosine - Pentose
Twelfth layer: Phosphate - Phosphate
Eleventh layer: Pentose - Cytosine - Guanine -Pentose
Tenth layer: Phosphate - - Phosphate
Ninth layer: Pentose - Adenine - Thymine - Pentose
Eighth layer: Phosphate - - Phosphate
Seventh layer: Pentose - Cytosine - Guanine - Pentose
Sixth layer: Phosphate - Phosphate
Fifth layer: Pentose - Thymine - Adenine - Pentose
Fourth layer: Phosphate - Phosphate
Third layer: Pentose - Adenine - Thymine - Pentose
Second layer: Phosphate - Phosphate
First layer: Pentose - Cytosine - Guanine - Pentose
Follow this pattern and keep note of the repeating Nucleotide pairs and the switching bases.
When you are four layers away from the middle of the DNA ladder, start “twisting” the ladder in a counterclockwise position to mimic the double helix strand of the DNA.
Secure the middle part with wire.
Continue the ladder pattern until you run out of balls.
Let the glue dry overnight.
You can also do this project using alternative materials, such as candies.