104 



HISTORY OF THE OCEANS 



(a) 



[b) 



(c) 



(d) 



ie) 



Fig. 1. Hierarchy of polymer complexes: (a) primary structure, no intrachain 

 links, polypeptide in /3 form; (b) secondary structure — coiling with intrachain 

 hydrogen bonds, polypeptide in a helix form; (c) tertiary structure, folded coils, 

 methemoglobin molecule (after Kendrew) ; (d) quaternary structure (homogeneous 

 type), linked groups of tertiary molecules, hemoglobin structure (after Perutz) ; (f) 

 quaternary structure (heterogeneous type) — linking of different types of ternary 

 protein and primary ribonucleic acid, tobacco mosaic virus (after Franklin). 



