Molecular biology, definition

As far as the 1953 selection of the Nobel Prize winners for science is concerned, one could look at this event as a perfect stage management of the Nobel Committee. The Nobel Prize for Medicine and Physiology went to Hans Krebs for the Citric acid cycle and enzymatic reactions , to Fritz Lipmann for Coenzyme A , and the Nobel Prize for Chemistry to Hermann Staudinger [7, p. 1064]. In addition, Watson and Crick had just rang in molecular biology definitely with their Nature article on their DNA model [18]. 

In contrast, RNA occurs in multiple copies and various forms (Table 11.2). Cells contain up to eight times as much RNA as DNA. RNA has a number of important biological functions, and on this basis, RNA molecules are categorized into several major types messenger RNA, ribosomal RNA, and transfer RNA. Eukaryotic cells contain an additional type, small nuclear RNA (snRNA). With these basic definitions in mind, let s now briefly consider the chemical and structural nature of DNA and the various RNAs. Chapter 12 elaborates on methods to determine the primary structure of nucleic acids by sequencing methods and discusses the secondary and tertiary structures of DNA and RNA. Part rV, Information Transfer, includes a detailed treatment of the dynamic role of nucleic acids in the molecular biology of the cell. 

Since the early 1970s a panel convened by the International Union of Pure and Applied Chemistry and the International Union of Biochemistry and Molecular Biology has been working to formulate recommendations for carbohydrate nomenclature that meet developing needs of research and electronic data handling, while retaining links to the established literature base on carbohydrates. The realization of these endeavors is presented here in the final document Nomenclature of Carbohydrates, which provides a definitive reference for current researchers, both in the text version and in the version accessible on the World Wide Web (http //www.chem.qmw.ac.uk/iupac/2carb/), where amendments and revisions are maintained. 

Biochemistry can be defined as the science concerned with the chemical basis of life (Gk bios life ). The cell is the structural unit of living systems. Thus, biochemistry can also be described as the science concerned with the chemical constituents of living cells and with the reactions and processes they undergo. By this definition, biochemistry encompasses large areas of cell biology, of molecular biology, and of molecular genetics. 

In close analogy with this biological definition, we will designate as molecular phenotype the ensemble of observable and computable properties of a chemical entity. These indeed are the observable expression of the core features of the... 

Phycomyces has aroused the interest of biologists for over a century. Yet, in the present mode of approach and definition of its aims, the research with this fungus, as it is being conducted nowadays, is clearly a child of the early period of molecular biology. 

So far, no attempts have been made to formulate a precise biochemical or biological definition of Hp s. This lack of an exact definition may be explained, at least to some extent, by the molecular heterogeneity of Hp s and by the insufficiency of our knowledge of the homeostasis and of the biological significance of Hp s. 

The oldest definitions of life, such as those given by Engels, Bernal, and Rolle, referred to what we have called life at the individual level. With the advent of molecular biology and the emergence of nucleic acids, genetics also became important when considering the definition of life. 

Dictionary of Biochemistry and Molecular Biology, 2nd ed., J. Stenesh (1989), Wiley Interscience (New York). Contains definitions of 16,000 terms. 

The final topic addressed in this chapter is the biosynthesis of the dithiolene cofactor ligand and its coordination to molybdenum and tungsten in the enzymes. Nature has clearly devised a synthetic process to overcome the twin difficulties of building a reactive dithiolene unit bearing a complicated and equally reactive pterin substituent. Molecular biology has been the tool to elucidate the steps in this complex process. Although the dithiolene formation step remains mainly a subject of conjecture, definitive information about the reagent molecule that will eventually be converted to a dithiolene is known. 

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