Carbon biological importance

The prostaglandins (qv) constitute another class of fatty acids with aUcycHc structures. These are of great biological importance and are formed by i vivo oxidation of 20-carbon polyunsaturated fatty acids, particularly arachidonic acid [27400-91-5]. Several prostaglandins, eg, PGE [745-65-3] have different degrees of unsaturation and oxidation when compared to the parent compound, prostanoic acid [25151 -18-9]. 

W.B. Nowall and W.G. Kuhr, Detection of hydrogen peroxide and other molecules of biological importance at an electrocatalytic surface on a carbon fiber microelectrode. Electroanalysis 9, 102-109 (1997). 

The careful study of at least five different carbonaceous chondrites establishes the fact that these meteorites contain carbon compounds of extraterrestrial origin and of great significance in chemical evolution. Their presence confirms that the chemical reaction paths producing biologically important monomer molecules occur in the far reaches of our solar system. 

Our goal in this chapter is to help you learn about organic chemistry, the chemistry of carbon. You will learn about the different types of organic compounds. We will also discuss biochemistry, including some biologically important compounds, such as proteins, carbohydrates, and so on. We will also familiarize you with some organic reactions. And finally, to do well, you must Practice, Practice, Practice. 

Most biologically important fatty acids have even numbers of carbon atoms in their skeletons. Palmitic acid, for example, has 16. Since palmitic acid has no carbon-carbon double bonds, it is considered saturated. An unsaturated fatty acid, such as oleic acid (also shown in Figure 16.3), possesses one or more carbon-carbon double bonds (C=C). 

The end window of the tube must be thin enough to permit the weaker radiations to enter the tube (aluminium, 6-8 mg cm-2 mica, 2 mg cm-2) but even so alpha particles and very weak beta emissions are either completely or partially absorbed. The emissions from the biologically important isotopes of tritium and carbon-14 fall into this category and alternative detectors should be used for these isotopes. 

Seawater studies require certified reference materials for biologically important dissolved components such as carbon (both inorganic and organic), nutrients, and trace metals, as well as for salinity, which is hydro-graphically important. A number of the committee s key recommendations therefore explicitly address these parameters. There is also a striking need for reference materials based on particulate matrices, where many of the analytical techniques used are matrix dependent and differ markedly... 

Due to the synthetic and biological importance of amines and a-aminoketones, acids and esters, the introduction of amino functionality into carbon nucleophiles provides a convenient and practical route for their synthesis "In addition, a number of electrophilic amination methodologies have been developed for the asymmetric synthesis of amines and a-aminocarbonyl compounds " ". 

Silicon compounds also differ from carbon compounds in their "handedness." Many biologically important carbon compounds have both right-handed and left-handed structures, which refers to the way the atoms in the compounds are organized. Only one of these structures is biologically active. Silicon, on the other hand, most often does not display handedness of any... 

---