Biochemistry [antikvár]

PREFACE This book is written for students who are taking their first and perhaps their only course in biochemistry, whether as undergraduates or as graduate or medical students. 1 undertook this task because 1 want to convey to students my picture of what this science has recently become. Biochemistry is no longer a mere catalog of the biological occurrence and enzymatic reactions of a large number of organic compounds. In the last few years it has acquired, along with many new facts, a set of organizing principles which have made it a much simpler field to comprehend, and, at the same time, a more powerful way of analyzing many important problems in biology. How has this come about? Each field of scientific study at some time in its evolution undergoes a profound transition in which a collection of widely scattered facts and hypotheses crystallizes into a logical pattern, unified by a few basic concepts. Biochemistry has been undergoing such a transition, stimulated by new experimental findings and new insights. Among these are the recognition of the principles of energy transfer in cells, the mechanisms by which the major metabolic pathways are regulated, the importance of membranes, ribosomes, and other ultrastructural elements of cells in their molecular activities, and the far-reaching conclusion that the amino acid sequence determines the three-dimensional conformation of protein molecules and thus their biological functions. The new knowledge of the molecular basis of genetics, which has transformed all of biology, has had the most profound Influence. Because of these developments biochemistry now has a central story, a leitmotiv, which 1 have tried to express in simple terms in the Introduction. This book is concerned primarily with biochemistry at the cell level, where its organizing principles are most clearly evident. Central concepts are emphasized rather than an encyclopedic treatment of biochemical details. There are four major parts in the book: 1. Biomolecules 2. Energy-yielding processes 3. Energy-requiring processes 4. Transfer of genetic information These are subdivided into what I believe is a logical progression of chapters, each of which is a manageable