Ribonucleic acid bases

Several features of small molecules render them ideal for use with complex biological systems and for complement classical genetic analysis and methods based on ribonucleic acid-based interference (RNAi). These features include the ability to offer nearly instantaneous temporal control,... 

A solution leading to a successful algorithm was recently found for the folding of ribonucleic acid (RNA) [36], Natural RNA polymers (figure C2.14.1) are mainly made up from four different bases . A, C, G and U. As with DNA, multiple hydrogen bonding favours the fonnation of G-C and A-U pairs [16, 37, 38] which leads to the appearance of certain characteristic stmctures. Loop closure is considered to be the most important folding event. 

Nucleic acids are acidic substances present m the nuclei of cells and were known long before anyone suspected they were the primary substances involved m the storage transmission and processing of genetic information There are two kinds of nucleic acids ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) Both are complicated biopolymers based on three structural units a carbohydrate a phosphate ester linkage between carbohydrates and a heterocyclic aromatic compound The heterocyclic aro matic compounds are referred to as purine and pyrimidine bases We 11 begin with them and follow the structural thread... 

Nucleic Acids. Phosphoms is an essential component of nucleic acids, polymers consisting of chains of nucleosides, a sugar plus a nitrogenous base, and joined by phosphate groups (43,44). In ribonucleic acid (RNA), the sugar is D-ribose in deoxyribonucleic acids (DNA), the sugar is 2-deoxy-D-ribose. 

The sugars are typically ribose (ribonucleic acids, RNA), or 2-deoxyribose (deoxyribonucleic acids, DNA). There are five common bases in nucleic acids adenine (A) thymine (T) uracil (U) cytosine (C) and guanine (G). DNA polymers incorporate the four bases. A, T, C, and G, and RNA, the set A, U, C, and G. 

Adding nucleotides to the 3 -oxygen of an existing structure is called elongation and leads ultimately to a polynucleotide. The most important polynucleotides ar e ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). As we shall see in later sections, the polynucleotide chains of DNA and some RNAs are quite long and contain hundreds of thousands of bases. 

As is well-known, nucleic acids consist of a polymeric chain of monotonously reiterating molecules of phosphoric acid and a sugar. In ribonucleic acid, the sugar component is represented by n-ribose, in deoxyribonucleic acid by D-2-deoxyribose. To this chain pyrimidine and purine derivatives are bound at the sugar moieties, these derivatives being conventionally, even if inaccurately, termed as pyrimidine and purine bases. The bases in question are uracil (in ribonucleic acids) or thymine (in deoxyribonucleic acids), cytosine, adenine, guanine, in some cases 5-methylcytosine and 5-hydroxymethylcyto-sine. In addition to these, a number of the so-called odd bases occurring in small amounts in some ribonucleic acid fractions have been isolated. 

The nucleic acids DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are biological polymers that act as chemical carriers of an organism s genetic information. Enzyme-catalyzed hydrolysis of nucleic acids yields nucleotides, the monomer units from which RNA and DNA are constructed. Further enzyme-catalyzed hydrolysis of the nucleotides yields nucleosides plus phosphate. Nucleosides, in turn, consist of a purine or pyrimidine base linked to Cl of an aldopentose sugar—ribose in RNA and 2-deoxyribose in DNA. The nucleotides are joined by phosphate links between the 5 phosphate of one nucleotide and the 3 hydroxyl on the sugar of another nucleotide. 

Sites and thermodynamic quantities associated with proton and metal ion interaction with ribonucleic acid, deoxyribonucleic acid and their constituent bases, nucleosides and nucleotides. R. M. Izatt, J. J. Christensen and J. H. Rytting, Chem. Rev., 1971, 71, 439-481 (229). 

Figure 35-6. A segment of a ribonucleic acid (RNA) molecule in which the purine and pyrimidine bases— guanine (G), cytosine (C), uracii (U), and adenine (A)—are held together by phosphodiester bonds between ribo-syl moieties attached to the nucieobases by N-giycosidic bonds. Note that the polymer has a polarity as indicated by the iabeied 3 -and 5 -attached phosphates.

Along with stomach, bile, and lactic acids, there are many other acids in the human body These include, but are not limited to, nucleic acids, amino acids, fatty acids, and vitamins such as folic and ascorbic acids. Nucleic acids, including RNA (ribonucleic acid) and DNA (deoxyribonucleic acid), are long chains of phosphates and sugar to which nucleotide bases are attached. The phosphate molecules in the backbone of RNA and DNA are derived from phosphoric acid. Therefore, DNA is very weakly acidic. 

The nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), which carry embedded in their complex molecules the genetic information that characterizes every organism, are found in virtually all living cells. Their molecules are very large and complex biopolymers made up basically of monomeric units known as nucleotides. Thus DNA and RNA are said to be polynucleotides. The nucleotides are made up of three bonded (linked) components a sugar, a nitrogenous base, and one or more phosphate groups ... 

The discovery of the base-paired, double-helical structure of deoxyribonucleic acid (DNA) provides the theoretic framework for determining how the information coded into DNA sequences is replicated and how these sequences direct the synthesis of ribonucleic acid (RNA) and proteins. Already clinical medicine has taken advantage of many of these discoveries, and the future promises much more. For example, the biochemistry of the nucleic acids is central to an understanding of virus-induced diseases, the immune re-sponse, the mechanism of action of drugs and antibiotics, and the spectrum of inherited diseases. 

Ribonucleic acid (RNA) Molecules including messenger RNA, transfer RNA, ribosomal RNA, or small RNA. RNA serves as a template for protein synthesis and other biochemical processes of the cell. The structure of RNA is similar to that of DNA except for the base thymidine being replaced by uracil. 

In view of the difficulty of hydrolyzing the pyrimidine nucleosidic linkages, ribonucleic acids have been hydrolyzed to a mixture of purine bases and pyrimidine nucleotides which is then separated by paper chromatography.132, 163 164 This method has been employed extensively for the analysis of ribonucleic acids, and gives reproducible results,166 but it has not been used to any great extent for deoxyribonucleic acids, probably because, under these conditions of hydrolysis, they yield some pyrimidine deoxy-ribonucleoside diphosphates.166... 

Nitrogenous base plus sugar moiety are called nucleosides. Ribonucleic acids (RNA) resemble DNA in that nucleoside monophosphates are joined through phosphodiester bonds. RNAs differ in that the sugars are p-D-ribose units and the pyrimidine uracil is found in place of thymine. Molecular structures and nomenclature for nitrogenous bases, nucleosides, and nucleotides are delineated in Table 2.2. 

Nucleation sites, in ferrosilicon, 22 516 Nucleation track membranes, 15 802 Nucleic acid bases, recognition of, 16 794 Nucleic Acid Database (NDB), 17 606 Nucleic acid probe assays, 16 380. See also DNA analysis Nucleic acid probes, 14 153 Nucleic acids, 17 602-643 20 444-447. See also Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)... 

Nucleic acids are the molecules in our cells that direct and store information for reproduction and cellular growth. There are two types of nucleic acids ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). Both of these nucleic acids are unbranched organic polymers composed of monomer units called nucleotides. These nucleotides are composed of a sugar molecule, a nitrogen base, and phosphoric acid. A single DNA molecule may contain several million of these nucleotides, while the smaller RNA molecules may contain several thousand. 

---