Radioisotopes and Life Processes The Understanding the Atom Series Nuclear energy is playing a vital role in the life of every man, woman, and child in the United States today. In the years ahead it will affect increasingly all the peoples of the earth. It is essential that all Americans gain an understanding of this vital force if they are to discharge thoughtfully their responsibilities as citizens and if they are to realize fully the myriad benefits that nuclear energy offers them. The United States Atomic Energy Commission provides this booklet to help you achieve such understanding. [Illustration: Edward J. Brunenkant] Edward J. Brunenkant, Director Division of Technical Information UNITED STATES ATOMIC ENERGY COMMISSION Dr. Glenn T. Seaborg, Chairman James T. Ramey Wilfrid E. Johnson Dr. Theos J. Thompson Dr. Clarence E. Larson _Radioisotopes_ AND LIFE PROCESSES by Walter E. Kisieleski and Renato Baserga CONTENTS INTRODUCTION 1 CELL THEORY: DNA IS THE SECRET OF LIFE 2 RADIOACTIVE ISOTOPES: THE BIOLOGICAL DETECTIVES 10 DNA SYNTHESIS: THE AUTOBIOGRAPHY OF CELLS 15 RNA SYNTHESIS: HOW TO TRANSLATE ONE LANGUAGE INTO ANOTHER 25 PROTEIN SYNTHESIS: THE MOLECULES THAT MAKE THE DIFFERENCE 35 CELL CYCLE AND GENE ACTION: LIFE IS THE SECRET OF DNA 37 ISOTOPES IN RESEARCH: PROBING THE CANCER PROBLEM 43 CONCLUSIONS 45 SUGGESTED REFERENCES 47 United States Atomic Energy Commission Division of Technical Information Library of Congress Catalog Card Number: 66-61908 1966; 1967(Rev.) THE COVER The cover design portrays the inter-relationships suggested by the title of this booklet: On a trefoil symbolizing radiation are superimposed a dividing cell, a plant, an animal, and a double helix of a molecule of deoxyribonucleic acid, a material unique in and fundamental to all living things. THE AUTHORS