- DNA has an alpha helix shape which consists of nucleotides. Nucleotides are made of pentose, phosphate, and a nitrogenous base. They have 2 types of bases; purines and pyrimidines. Pyrimidines consist of a single ring structure with thymine and cytosine while purines have a double ring structure with adenine and guanine. Since there is complementary base pairing between the nucleotides adenine and thymine as well as guanine and cytosine, they bond together to create the alpha helix shape that DNA has. DNA also consists of antiparallel strands meaning that the sugar and phosphate are aligned in opposite directions on each backbone of the DNA helix.
- The activity helps model the structure as it clearly shows the nucleotides and how they bond together to create the double helix shape. However, it is hard to see that the backbone contains sugar as well as phosphate. Next time we should add a different colour bead for sugar and also maybe use a different colour bead for the phosphate so it can stand out better from the blue pipe cleaner.
Everything looks good! But maybe you could mention that the strand has 2 backbones. Everything else has great detail.