Mar13
I would suggest using wire or pipe cleaners as a framework, and using beads, candies with holes, colored marshmallows, or some other item that you can support on the framework to represent sugars, phosphate groups, and the four nitrogenous bases. That means you need six different colors or shapes, and a way to hold them together and support them. You also need to show that the DNA strands are anti-parallel and that they are joined by the appropriate number of bonds between bases. Bases must also be attached to the sugars, not the phosphates, and base pairing rules must be followed. Finally, the model must show the helical shape of DNA.