The origin of life is one of the most interesting and challenging questions in biology. This article discusses relevant contemporary theories and hypotheses about the origin of life, recent scientific evidence supporting them, and the main contributions of several scientists of different nationalities and specialties in different disciplines. Also…

This paper presents an activity that engages students in model-based reasoning, requiring them to predict the behavior of the trp and lac operons under different environmental conditions. Students are presented six scenarios for the "trp" operon and five for the "lac" operon. In most of the scenarios, specific mutations have…

Proposes models for the evolution of the genetic code and translation mechanisms. Suggests that the translation process is so complex and precise that it must have evolved in many stages, and that the evolution of the code was influenced by the constraints imposed by the evolving translation mechanism. (EB)

Describes the rapid advance of molecular genetics over the past 20 years that have accounted for the origin of mutations. This research has revealed that variation within species is much greater than Darwin postulated. (Author/MA)

Biological evolution can be carried out in the laboratory. With new knowledge available in genetics, possibilities are raised that genetic characters can be transferred in the future to embryos according to a predetermined plan. (PS)

Proposes a molecular mechanism for the coupling of phosphorylation to electron transport in both mitochondria and chloroplasts. Justifies the proposed reaction schemes in terms of thermodynamics and biochemical data. Suggests how areobic respiration could have evolved. (EB)

Can genetic evolution be controlled by man in a manner which does not violate a civilized, humane, and democratic ethos? The genetics of health and illhealth and of normal variation are discussed with respect to this question. (PEB)

Describes the unicellular microorganisms of three billion years ago. Explains how these primitive cells gave rise to biochemical systems and the present oxygen-rich atmosphere. Numerous diagrams, charts, and illustrations. (MA)

An argument is made in favor of imperfect or unfinished evolution based on some metabolic pathways in which it seems that intelligent design would have done better. The case studies noted indicate the absence of highly intelligent design and are not intended as comprehensive collection but as a limited sample of inefficient situations in…

Presents various ideas on the origin of life including very early ideas, Oparin's view, and an alternative view related to carbonaceous chondrites. Outlines one currently tenable hypothesis in the formation of the solar system and explains the method involved in detecting polyatomic molecules in dark nebulae. (GS)

Describes the Miller and Urey experiment to synthesize organic compounds. Includes subsequent research and relates these studies to the formation of one-celled organisms in an oxygen-free atmosphere. (MA)

Osmotic aspects of aqueous solutions that are usually disregarded in biochemistry textbooks are presented. This article discusses the osmolarity of seawater, evolution of organisms over geological time, ionic adaptation of cells, ionic concentrations in bacteria, osmolytes and blood electrolytes in water-stressed organisms and land vertebrates,…

The hazards posed by new techniques of genetic manipulation have prompted scientists to regulate and in some cases restrict their own basic investigations. Describes some possible applications of the new techniques and outlines the established research guidelines. (GS)

Presents genetical and biochemical data to show that the conclusion presented by Dyer (EJ 036 108) is by no meas settled. Evidence to support the concept: evolution by selectively neutral polymorphisms is inconclusive. (AL)