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Building the helix

Models are built using a basic repetitive structure. Three pieces are required, the 135 degree green connectors, the white rods, and the blue rods. The green connectors serve as the deoxyribose sugar units of the helix backbone. Phosphodiester bonds linking the sugar units are represented by the white rods. Hydrogen bonded base pairs are represented by blue rods.  

The connections for the simplest model are illustrated below. The double helix is composed of two backbones held together by hydrogen bonded bases. Each backbone is formed by joining green connectors in a chain using the white rods attached to the outer slots. The backbones are cross linked with the blue rods. Blue rod attachment should be at the third slot of the green connectors on each chain. Because the chains are anti-parallel, on one chain attachment should be at the  third slot from the left and on the other chain, third slot from the right.


Follow the arrows above to produce the segment pictured below. When the second blue rod is attached, the two backbones will start to twist around each other.