The K"NEX DNA, Replication and Transcription set is designed to aid in teaching the structure and function of the nucleic acid molecules that make up DNA (deoxyribonucleic acids) and RNA (ribonucleic acids). The Teacher"s Guide provides lessons designed to take students through three instructional modules: I. DNA Structure II. Replication & Transcription III. Coding, Translation, and Mutations Excellent demonstration tool at the elementary school level. Curriculum aligned to National Science Education standards for grades 5 - 12.Set includes 521 K"NEX parts - enough to build 19 DNA and mRNA models, up to two at a time! Supports 2 - 3 students working as a team. Grades 5 - 12. Building instructions and teacher"s guide aligned to national standards included. Packaged in a strong storage tray with Snap-on lid.