There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact. Mark Twain The recent explosion in ou. r knowledge of basis physiologic processes, molecular biology, and genetic regulatory mech anisms has resulted, in large measure, from a single concep tual advance: the realization that, at the molecular level, evolutionarily divergent organisms are more similar than different. Thus, in Escherichia coli and Homo sapiens, the enzymatic pathways for the utilization of galactose and glu cose are the same, although more than a single sequence of enzymatic reactions can lead to the utilization of either sugar. Also, extensive studies have revealed the essential of the genetic code, the mechanism of decxy universality ribonucleic acid (DNA) repli~ation, and the processes by which genetic information is transcribed to ribonucleic acid (RNA) and RNA is translated into protein. A detailed com parative examination of anyone area of biologic interest, of course, reveals differences among phylogenetically distinct organisms. In prokaryotic organisms protein synthesis is initiated with N-formyl methionyl-transfer RNA (tRNA), whereas methionyl tRNA serves this function in the cyto plasm of the eukaryote. Mechanistic differences may have evolved to accommodate the differing degrees of com plexity of cellular construction or to coordinate functions of differentiated cells in a multicellular organism. Yet, we must realize that the basic, life-endowing molecular pro cesses had to exist prior to extensive evolutionary diverg ence-before the appearance of two distinct cell types.

Inhalt
1 Introduction: Cell Structure and Function.- 2 Constituents of Biological Membranes.- Membrane isolation.- Membrane composition.- Membrane lipids.- Membrane proteins.- 3 Structure of Membranes and Serum Lipoprotein Complexes.- Soap molecules in aqueous solution.- Biological membranes.- Serum lipoprotein complexes.- Fluidity of membrane constituents.- Membrane action of anesthetics.- 4 Biological Consequences of Membrane Fluidity and Fusion.- Membrane biogenesis.- Intercellular junction formation.- Myogenesis.- Phagocytosis.- Secretion.- 5 Transmembrane Solute Transport Mechanisms.- Ion-transporting antibiotics.- Group translocationthe bacterial phosphotransferase system.- Group translocationintestinal disaccharidases.- Active transport mechanisms in intestinal epithelial cells.- Energy interconversion and active transport in bacteria.- 6 Sensory Perception I: Chemoreception.- Bacterial chemoreception.- Chemotactic responses of solitary eukaryotic cells.- The chemical regulation of insect behavior.- The chemical senses of mammals.- 7 Sensory Perception II: Transmission Mechanisms.- The resting membrane potential and action potentials.- Excitability-inducing material.- Ion-conducting channels in excitable membranes.- Bioelectric control of ciliary activity in Paramecium.- Photoreception in the rod cell of the mammalian eye.- Bacterial photoreception and transmission.- 8 Hormonal Regulation of Cellular Metabolism.- The insulin receptor.- Possible mechanisms of hormone regulation.- Regulation of bacterial metabolism.- Regulation of cellular cyclic AMP levels.- 9 Cell Recognition.- Adhesion of bacteriophage to bacterial hosts.- Heterotypic adhesionsexual agglutination in yeast.- Homotypic adhesionsponge aggregation.- Animal cell adhesion and malignancy.- 10 Roleof the Plasma Membrane in Growth Regulation and Neoplasia.- Growth of normal and transformed animal cells.- Positive growth control.- Negative growth control.- Changes in membrane structure and function associated with transformation.- Microbial systems for studying the molecular basis of neoplastic transformation.- Mammalian growth regulation and membrane biology.- Index 125.