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.

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

WALTER E. KISIELESKI is an Associate Scientist in the Division of Biology and Medicine of the Argonne National Laboratory. He was formerly associate professor of chemistry at Loyola University in Chicago. His undergraduate studies were at James Millikin University in Decatur, Illinois, and his graduate studies were at the University of Chicago. He received an Honorary Doctor of Science degree from James Millikin University in 1962. In 1958 he was a delegate to the Second Atoms for Peace Conference in Geneva, Switzerland. He was visiting lecturer in the department of biochemistry at the University of Oslo in Norway in 1963. Dr. Kisieleski is shown operating an automatic windowless strip counter that scans paper chromatograms and thus locates labeled substances.

RENATO BASERGA was born in Milan, Italy, and received a medical degree from the University of Milan in 1949. He is presently research professor of pathology at the Fels Research Institute at Temple University Medical School in Philadelphia, and associate editor of the journal, Cancer Research. Formerly he was associate professor of pathology at Northwestern Medical School in Chicago, where he was the recipient of a Research Career Development Award from the National Institutes of Health.

Radioisotopes
AND LIFE PROCESSES

By WALTER E. KISIELESKI
and RENATO BASERGA

INTRODUCTION

Here and elsewhere we shall not obtain the best insight into things until we actually see them growing from the beginning.

Aristotle

The nature of life has excited the interest of human beings from the earliest times. Although it is still not known what life is, the characteristics that set living things apart from lifeless matter are well known. One feature common to all living things, from one-celled creatures to complex animals like man, is that they are all composed of microscopic units known as cells.

The cell is the smallest portion of any organism that exhibits the properties we associate with living material. In spite of the immense variety of sizes, shapes, and structures of living things, they all have this in common: They are composed of cells, and living cells contain similar components that operate in similar ways. One might say that life is a single process and that all living things operate on a single plan.

The past few years have been a time of rapid progress in our understanding of the mechanisms that control the function of living systems. This progress has been made possible by the development of new experimental techniques and by the perfection of instruments that detect what happens in the tiny world of molecules. Prominent among the methods that have contributed to the explosive growth in our understanding of biology is the use of radioactive isotopes as laboratory tools.

In this booklet we shall attempt to give an account, in chemical terms, of the materials from which living matter is made and of some of the chemical reactions that underlie the manifestations and the maintenance of life. To accomplish this, we have chosen to describe three types of molecules that have become the basis of modern biology: deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and