Organic chemicals, elements found

Not surprisingly, only about 20 of the chemical elements found on Earth are used by living organisms (Chapters 3 and 8). Most of them are common elements. Rare elements are used, if at all, only at extremely low concentrations for specialized functions. An example of the latter is the use of molybdenum as an essential component of nitrogenase, the enzyme that catalyzes the fixation of elemental dinitrogen. Because they are composed of common elements, living organisms exert their most profound effects on the cycles of those elements. 

An alkaloid is a complex organic chemical substance found in plants, which characteristically combines nitrogen with other elements, has a bitter taste, and typically has some toxic, stimulant, analgesic effects. There are many different alkaloids, 30 of which are found in the opium plant. While morphine is the most important alkaloid in opium—for its natural narcotic qualities as well as providing the chemical structure for heroin—another alkaloid, codeine, is also sought after for its medicinal attributes. Other alkaloids include papaverine, narcotine, nicotine, atropine, cocaine, and mescaline. While the concentration of morphine in opium varies depending on where and how the plant is cultivated, it typically ranges from 3 percent to 20 percent. 

Organic polymers provide one of the most versatile groups of materials and have widespread uses. Due to some inherent deficiencies, mainly poor heat and flame resistance, these materials suffer from limitations in certain areas of application. The resistance of polymers to high temperatures and flame may be increased by the incorporation of both aromatic rings and certain chemical elements in the polymer chain. It has been found that phosphorus, present either as a constituent in the polymer chain or incorporated as an additive in the form of a phosphorus compound to the polymer system, can make polymers flame retardant [109]. 

A systematic difference is found, supported by indirect evidence that from experience precludes any explanation other than effect observed. This case does not necessarily call for a statistical evaluation, but an example will nonetheless be provided in the elemental analysis of organic chemicals (CHN analysis) reproducibilities of 0.2 to 0.3% are routine (for a mean of 38.4 wt-% C, for example, this gives a true value within the bounds 38.0. .. 38.8 wt-% for 95% probability). It is not out of the ordinary that traces of the solvent used in the... 

In addition to the dissolved elements and compounds in the oceanic water column, a wide variety of water column chemicals are found in marine organisms and organic detritus. For example, a milliliter of surface seawater can contain on the order of 10 million viruses, 1 million bacteria, 100,000 phytoplankton, and 10,000 zooplankton [9]. With the advent of soft ionization processes for mass spectrometry systems, scientists have been able to study these marine organisms at molecular level. The use of electrospray ionization (ESI see Section 2.1.15), atmospheric pressure chemical ionization... 

The extraordinary ability of carbon to combine with itself and other chemical elements in different ways is the basis of organic chemistry. As a consequence, there is a rich diversity of structural forms of solid carbon because it can exist as any of several allotropes. It is found abundantly in nature as coal, as natural graphite and also in much less abundant form as diamond. 

Very little is known about the chemical structure of coke. The chemical analyses of different coked catalysts have indicated that coke is not pure carbon, but is composed of 90-95% carbon, 5-7% hydrogen, 0-2% nitrogen, and traces of other elements found in the processed oil. The existence of different organic bonds indicates that coke has a macromolecular structure. This macromolecular structure can be broken down by certain reactive and strong solvents. 

Biomolecules are naturally occurring chemical compounds found in living organisms that are constructed from various combinations of key chemical elements. 

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