The Nucleic Acids DNA and RNA

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  

In each nucleotide, the three components are joined to each other and arranged in the repeating sequence sugar, phosphate group, nitrogenous base  

In the molecules of the polynucleotides, those of DNA and RNA, the nucleotides are linked to each other, forming long, continuous strands in the pattern 

Since the sugar in DNA is deoxyribose, the polynucleotide that makes up DNA can be written as 

In different molecules of DNA the four nitrogenous bases (adenine, cytosine, guanine, and thymine) appear in different order, and the genetic 

---

Those nucleosides found in the nucleic acids DNA and RNA involve the joining of ribose of deoxyribose to a purine or a pyrimidine base. One such nucleoside is adenosine, in which a nitrogen of adenine is linked to carbon 1 of the pentose, ribose. In this form it is a component of RNA but as a phosphory-lated derivative of adenosine (e.g. ATP), which is a high energy compound, it fulfils an important role in metabolism. The dinucleotides NAD and NADP are two cofactors necessary for many enzymic transformations and these also contain /V-glycosides of ribose phosphate. Other important nucleosides are found... 

The nucleic acids DNA and RNA feature diesters of phosphoric acid... 

Whilst many biochemicals are mono-esters of phosphoric acid, the nucleic acids DNA and RNA (see Section 14.2) provide us with good examples of diesters. A short portion of one strand of a DNA molecule is shown here the most significant difference in RNA is the use of ribose rather than deoxyribose as the sugar unit. 

Nucleotides serve as the building blocks for synthesis of the nucleic acids DNA and RNA. 

The purines are an important class of heterocycles in which an imidazole ring is fused to a pyrimidine ring. Uric acid (the main product of nitrogen metabolism in birds and reptiles), caffeine (present in coffee), and adenine and guanine (nitrogen bases present in the nucleic acids DNA and RNA) are examples of naturally occurring purines. 

The nucleic acids, DNA and RNA, store genetic information in living organisms and are responsible for translating this information into the structure of proteins. Because their structure and function are discussed in great detail in modem biochemistry texts, this chapter concentrates on the organic chemical aspects of these important biomolecules. 

The chapter begins with a discussion of the structure of nucleosides and nucleotides. Then the structure of the nucleic acids, DNA and RNA. the polymers formed from nucleotide monomers, is presented. The function of these polymers in the replication, transcription, and translation of genetic information is briefly addressed. Next, the organic chemistry involved in determining the sequence of DNA is presented. Finally, the synthesis of small DNA molecules in the laboratory is discussed. 

Nucleotides are large molecules that combine into the nucleic acids (DNA and RNA), which carry genetic information. 

Examination of the genealogical mimicry involved in the construction and synthesis of Starburst/cascade dendrimers places this activity at the interface between chemistry and biology. Essentially all genealogical phenomena in biological systems involve and evolve around two generic classes of compositions, namely (a) nucleic acids and (b) proteins. The nucleic acids, DNA and RNA are estimated to be over three billion years old by radioactive carbon dating (see Ref. 206) (see Fig. 45). 

Phosphorus can be found in both plants and animals. Thus, bones, teeth, nerves, and muscle tissues contain phosphorus. The nucleic acids DNA and RNA contain phosphorus as well. 

The nucleic acids DNA and RNA are well suited to function as the carriers of genetic information by virtue of their covalent structures. These macromolecules are linear polymers built up from similar units connected end to end (Figure 5.1). Each monomer unit within the polymer consists of three components a sugar, a phosphate, and a base. The sequence of bases uniquely characterizes a nucleic acid and represents a form of linear information. 

Phosphorus plays the starring role in many body functions. As a key ingredient of the energy production process in every cell of the body, adenosine triphosphate helps transform glucose into energy and carbon dioxide. Most enzyme reactions involving B-complex vitamins as cofactors can only take place in the presence of phosphorus. As an essential part of the nucleic acids DNA and RNA, it influences cell reproduction... 

The cellular role of the nucleic acids DNA and RNA is in the formation, or synthesis, of protein, which is by itself a polymer of various amino adds joined together. Whereas the acronym RNA stands for ribonucleic acid, the acronym DNA stands for deoxyribonucleic acid. The designator ribo- indicates the involvanent of ribose, a five-carbon sugar with the stoichiometric formula C5HJ0O5. 

The fiber diffraction technique has been used to determine the structures of a wide variety of synthetic and biological molecules including structural proteins such as collagen and keratin, a range of helical conformations of the nucleic acids, DNA and RNA, and polysaccharides. In the case of the B form of DNA, early fiber diffraction patterns, which were not fully crystalline, still provided sufficient information to show... 

The nucleic acids DNA and RNA are composed of smaller repeating units called nucleotides. The reaction to form a phosphate-ester linkage between two nucleotides can be approximated as follows ... 

While at Manchester, Todd began his work on nucleotides. These compounds are the stmctural units of the nucleic acids DNA and RNA. In 1949, while at Cambridge, he synthesized adenosine triphosphate (ATP Figure... 

---