Building a DNA model helps students understand chromosomes, genes and the structure of the DNA molecule. A well-constructed DNA model also improves the quality of a classroom presentation. The simplified DNA model can be made using a variety of materials, and the goal of the project is to create a multicolour, ladder-like model that represents the double-helix molecule.
DNA Candy Molecule
The key to making an effective DNA model is using multiple colours that are arranged in a specific pattern to form a structure that looks like a twisted ladder. A DNA model can be made using liquorice sticks in two colours that make up the rails to the ladder. The liquorice is cut in 1 inch pieces and then threaded onto fishing line in alternating colours. Next, four different colour gummy bears are pressed onto tooth picks or small dowels in coloured pairs. Between each brightly coloured candy bear is a small marshmallow. The final step involves using the gummy bear and marshmallow toothpicks as "rungs" for the ladder. The toothpicks are pressed into the red liquorice pieces, and the black liquorice pieces on each side of the ladder are skipped, to represent the DNA molecule chemical composition.
A simple way to make a DNA model is to use styrofoam balls, double-ended toothpicks, and a wooden stand. Poster paint, a paint brush, glue and string are also needed. The balls are painted to represent the different molecules involved in a DNA structure. Smaller and larger balls represent different types of molecules. The student starts from the base by connecting balls in pairs at the end of the toothpicks, and then the molecule pairs are stacked on top of one another to create the twisted double-helix DNA structure.
Fishing Line Model
Students can also make a DNA model by using fishing line, chenille pipe cleaners in four different colours, and dried pinwheel and ziti pasta. The DNA molecule ladder rang is made by attaching different coloured pasta pieces to the ends of the chenille pipe cleaners. The pipe cleaners are then strung together with fish line at the centre point of each rang The fishing line and different colour chenille stems can be used to help the students understand how the components fit together to form DNA. Pinwheel and ziti cut pasta is used to represent the sugar and phosphate components of the molecule. This model will be less rigid and more difficult to display than a model made with toothpicks and candy pieces.
Gumdrops and Licorice
An easy way to make a DNA model is to use gumdrops in four different colours, liquorice sticks and toothpicks. The students can take gumdrops in any two colours and thread them onto the ends of a toothpick. The gumdrops are then stacked on top of one another using toothpicks to build the structure. Each pair of gumdrops represents a matched phosphate group while the toothpick represents the base chemicals that stretch between the phosphates.