acids. The achievements of molecular biology testify to the success of material science in a realm which, until recently, appeared totally enig­ matic and mysterious. Further scientific developments should bring to mankind vast developments both in theoretical knowledge and in practical applications, namely, in agriculture, medicine, and technology. The purpose of this book is to explain molecular biophysics to all who might wish to learn about it, to biologists, to physicists, to chemists. This book contains descriptive sections, as well as sections devoted to rigorous mathematical treatment ofa number of problems, some of which have been studied by the author and his collaborators. These sections may be omitted during a first reading. Each chapter has a selected bibliography. This book is far from an exhaustive treatise on molecular biophysics. It deals principally with questions related to the structures and functions of proteins and nucleic acids. M. V. Vol'kenshtein Leningrad, September, 1964 CONTENTS Chapter 1 Physics and Biology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Physics and Life. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Molecular Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Molecular Biophysics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Thermodynamics and Biology. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Information Theory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Chapter 2 Cells, Viruses, and Heredity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 The Living Cell. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Cell Division. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Viruses and Bacteriophages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 BasicLaws of Genetics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Mutations and Mutability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Genetics of Bacteria and Phages . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Chapter 3 Biological Molecules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Amino Acids and Proteins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Asymmetry of Biological Molecules . . . . . . . . . . . . . . . . . . . . . . . 87 Primary Structure of Proteins . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Nucleic Acids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Some Biochemical Processes in the Cell. . . . . . . . . . . . . . . . . . . . 109 Chapter 4 Physics of Macromolecules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Physical Properties of Macromolecules . . . . . . . . . . . . . . . . . . ..