4. Parts : Trivalent Carbon trivalent-1 , Nitrogen trivalent-1 , Oxygen trivalent-1 , and Double bond unit for Prine. Carbon trivalent-2 , Nitrogen trivalent-2 , Oxygen trivalent-2 Trivalent part has 3 bonds. In trivalent-1part,two bonds are Horn-shaped working as male ( + ) and the other one works as female( - ) using hole. Contrary trivalent-1 part , Trivalent-2 part has Horn-shaped one bond working as male ( + ) and two bonds working female( - ) Nitrogen trivalent is originally prepared for Nitrogen of the peptide bond . which is used when amino acid condenses into peptides. Carbon trivalent ,same shape as above but colored in black, is usefull as a part at the location C4,C5 and C8 of the purine ring Be sure to place the smaller angle 114° for the interior angle of pentagon of purine ring and larger angle 123° for the one hexagon. See Bio-100,101,102 Bio-210,211 Double bond unit for Prine in supplementary parts is a part suitable at the location C4 and C5 Fig.5 Item No. Name Bond Length Bond Arrangement Color Angle Shape Bio-11-1 Carbon trivalent-I 0.60 0.62 0.70 Black 114° 123° 123° Bio-12-1 Nitrogen trivalent-I Blue Bio-13-1 Oxygen trivalent-I Red Bio-28 Phosphorus Tetrahedral-I 1.32 Grey Item No. Name Bond Length Bond Arrangement Color Angle Shape Bio-19 Carbon trivalent-II 0.60 0.62 0.70 Black 114° 123° 123° Bio-20 Nitrogen trivalent-II Blue Bio-21 Oxygen trivalent-II Red HGS Molecular Structure Model HGS HINOMOTO PLASTICS CO., LTD. 1-10-24, Meguro-Honcho, Meguro-ku, Tokyo, Japan PHONE: +81-3-3714-7226 FAX: +81-3-3714-4657 E-MAIL(technical support): hgs@po.sphere.ne.jp E-MAIL(order support): t_kaneko@maruzen.co.jp