The remarkable development of molecular biology has had its counterpart
in an impressive growth of a segment of biology that might be described
as atomic biology. The past several decades have witnessed an explosive
growth in our knowledge of the many elements that are essential for life
and maintenance of plants and animals. These essential elements include
the bulk elements (hydro- gen, carbon, nitrogen, oxygen, and sulfur),
the macrominerals (sodium, potas- sium, calcium, magnesium, chloride,
and phosphorus), and the trace elements. This last group includes the
ultra trace elements and iron, zinc, and copper. Only the ultratrace
elements are featured in this book. Iron has attracted so much research
that two volumes are devoted to this metal-The Biochemistry of Non-Heme
Iron by A. Bezkoravainy, Plenum Press, 1980, and The Biochemistry of
Heme Iron (in preparation). Copper and zinc are also represented by a
separate volume in this series. The present volume begins with a
discussion of essentiality as applied to the elements and a survey of
the entire spectrum of possible required elements.