Teach the primary and secondary structure of DNA with this durable, attractive model. Colorful pieces reveal the polymeric nature of DNA, including base pairs, phosphate ester linkages, and ribose units. Adenine and thymine bases are attached by 2 pegs to model their 2 hydrogen bonds; 3 pegs link cytosine and guanine base pairs. Model even shows major and minor grooves. Size, 18" H.