Atomic, biological, chemical

Molecule A chemical made up of two or more atoms. The atoms in a molecule can be the same (an oxygen molecule has two oxygen atoms) or different (a water molecule has two hydrogen atoms and one oxygen atom). Biological molecules, such as proteins and DNA, can be made up of many thousands of atoms. [NIH]... 

His serious interest molecular biology began about 1935. He was intrigned by the question of how protein molecules were constructed. As a professor at the California Institute of Technology, he was known forgiving "baby toy lectures because he made models of molecules out of string, rod- and-ball structures, and plastic bubbles in different colors, shapes, and sizes. One day, working with paper, he sketched atoms and chemical bonds and folded them in different ways and discovered the basic structure of the protein molecule,... 

A radioactive isotope (radioisotope) is an unstable isotope of an element that decays into a more stable isotope of the same element. They are of great use in medicine as tracers (to help monitor particular atoms in chemical and biological reactions) for the purpose of diagnosis (such as imaging) and treatment. Iodine (-131 and -123) and Technetium-99 are used for their short half-lives. 

The essential role of molybdenum in a variety of fundamental biological processes has been known for a long time. Although tungsten and molybdenum have very similar atomic and ionic radii and comparable coordination chemistry, a substitution of Mo by W always causes an inactivation of the enzymes. This elucidates the enormous selectivity of biological, chemical reactions. In contrast, the substitution of W by Mo was possible in some cases without any loss in activity, but not in all cases. 

PROBLEM 6.14 The mass 82 isotope of bromine ( Br) is radioactive and is used as a tracer to identify the origin and destination of individual atoms in chemical reactions and biological transformations. A sample of 1,1,2-tribromocyclohexane was prepared by adding Br— Br to ordinary (nonradioactive) 1-bromocyclo-hexene. How many of the bromine atoms in the 1,1,2-tribromocyclohexane produced are radioactive Which ones are they ... 

Typical of their stated intent to use chemical and biological weapons is a statement by a senior Soviet admiral, in 1958. A future war will be distinguished from all past wars in connection with the mass employment of military air force devices, rockets, weapons, and various means of destruction such as atomic, hydrogen, chemical, and bacteriological weapons. ... 

Novel properties in biological, chemical, and physical systems can be approximately obtained at dimensions between 1 nanometer to lOOnano-meters. These properties can differ in fundamental ways from the properties of individual atoms and molecules and those of bulk materials [1], Nowadays, advances in nanoscience and nanotechnology indicate to have major implications for health, wealth, and peace. Knowledge in this field due to fundamental scientific advances, will lead to dramatic changes in the ways that materials, devices, and systems are understood and created. Nanoseience will redirect the scientific approach toward more generic and interdisciplinary research [1,2]. 

My own contribution as a chemical physicist to this aim may appear somewhat of an intrusion in a discussion dedicated to biological problems. My main point is that most of the specific molecular functions of proteins would become badly smudged, or would even be obliterated, in the absence of water which is normally present and which acts as supporting fluid for the various more distinctive assemblies of atoms in biological catalysts I can only make quite brief remarks on my theme Why Water . Each of these remarks summarizes an invitation to a research programme in biological chemical physics. 

Staining, in the most general terms, involves the incorporation of electron dense atoms into the polymer, in order to increase the density and thus enhance contrast. In this general sense of the term, staining will refer to either the chemical or the physical incorporation of the heavy atom. Biological materials often have sites, or specific structures, that react with various stains to yield contrast and thus information about these struc-... 

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