Why People Need Iron and Animals Make Magnets ... - ACS Publications


Why People Need Iron and Animals Make Magnets...

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Book & Media Reviews

Jeffrey Kovac University of Tennessee Knoxville, TN 37996-1600

Iron, Nature’s Universal Element: Why People Need Iron and Animals Make Magnets by Eugenie Vorburger Mielczarek and Sharon Bertsch McGrayne Rutgers University Press: New Brunswick, NJ, 2000. 204 pp. includes figures. ISBN: 0-8135-2831-3. $30 reviewed by Linda H. Doerrer

Iron, Nature’s Universal Element: Why People Need Iron and Animals Make Magnets is a well-researched and extremely well-written book. I found it a highly entertaining read as well as an informative one. It is suitable for the lay reader who only encounters details about iron on a vitamin bottle, but is also valuable for any scientist with an interest in iron, and particularly those teaching undergraduates about it. I would have loved this book as a high school student and imagine the text accessible to advanced middle school students also. The different aspects of iron will not be new to most chemists, but this collection of so many between two covers and explained in such entertaining detail is an accomplishment. The main strength of the text is its unique approach. The story of iron is told from the beginning of the earth’s history (nuclear synthesis is not much discussed, though that is one of the few topics I missed in this book) through to contemporary human health concerns. Chapter 1 contains a brief review of atomic structure in a simplistic Bohr-type atom, and describes the physical distribution of iron throughout the earth (core, mantle, and crust). The important distinction between divalent and trivalent iron is made in the context of the early earth atmosphere. The iron distribution in terrestrial and aquatic environments as well as iron use by primitive organisms are discussed leading easily, as all chapters in this text do, to the next chapter. This chapter also typifies the rest of the book by presenting what once was a puzzle in natural science and its elucidation by a particular researcher, in this case our understanding archaebacteria’s familial relationship to other life forms. Chapter 2 describes the advent of oxygen gas on earth as a result of production by photosynthetic organisms. This development was catastrophic for most of the contemporary life forms, and the reasons are clearly explained. Chapter 3 uses the basic chemical ideas developed so far to explain the challenges facing organisms that need soluble, divalent iron in an aqueous and oxidizing environment. The authors explain iron entrapment and storage in small and large organisms, and the importance of reversible processes.

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Iron transport within biological systems and common human metabolic disorders with these processes are also described. Chapter 4 contains a brief synopsis of basic ferro- and antiferromagnetic behavior in the context of magnets in motile organisms. The discovery of magnetic bacteria is highlighted. Chapter 5 is the longest in the book and focuses on hemoglobin and myoglobin. A modest introduction to proteins is sufficient to appreciate the subtle factors regulating these molecules, but not overwhelm the reader. Dioxygen use by a variety of different vertebrates is discussed, including humans in utero, horses, and whales. Many human diseases that the reader will have heard of are explained in terms of iron-heme unit dysfunction, and some encouraging prospects for treatment are also included. Chapter 6 returns to magnetic iron and its use as a guide by migrating organisms. The astounding accuracy and consistency with which many animals migrate around the globe is demystified somewhat by an explanation of the earth’s magnetic field and the environmental stimuli to which many animals respond. Pigeons, songbirds, sea turtles, and many other organisms are discussed. Chapter 7 brings the reader back to the global picture of Chapter 1, focusing on the 21st century ecosystem and our dependence on iron. The nitrogen cycle is explained as well as the challenging problem of dinitrogen activation and the impressive ability of some microorganisms to do this under mild conditions. Chapter 8 focuses on iron as an essential element in the human diet. The problem of iron deficiency in many poor families occurs in countries world wide. The inability of iron supplements to ameliorate earlier diet deficiencies pointedly emphasizes the need for humans to have adequate iron throughout their lives. An extensive bibliography will guide the interested reader to more details. References to the original literature predominate. There is also a glossary of terms, primarily useful for review, or perhaps to introduce terms to junior high or high school students. Each chapter has several black and white figures that thoughtfully complement the text, including photographs, explanatory sketches, graphs from the literature, and editorial cartoons. I highly recommend this book. My undergraduate inorganic students were fascinated by many examples and the way the authors connect them. The text could complement an environmental science course, serve as an example for writing about science to a lay audience, supplement biochemistry or bioinorganic chemistry classes, or just entertain you on your next travel segment. Linda H. Doerrer is in the Department of Chemistry, Barnard College, New York, NY 10027; [email protected].

Journal of Chemical Education • Vol. 79 No. 7 July 2002 • JChemEd.chem.wisc.edu