Biological Role of Phosphate Macromolecules

In order to maintain the life process, it is necessary to pass on specific information from one generation of organisms to the next. Such information is vital, for it allows the continuation of those traits or properties of the organism that insure survival. This information must be stored, to be used at an appropriate time, much as data may be stored and played on a tape recorder. As such, the job of information storage and processing must have a molecular basis. Indeed, it is not difficult to imagine some of the properties that are requisite for a molecular biological tape.  

An ordered structure suggests the presence of five- and six-membered rings, and not chains. Perhaps the simplest to imagine are hydrocarbons such as benzene, naphthalene, or indene. However, these molecules are quite hydrophobic. This is disadvantageous as biological processes are carried out in aqueous media. Furthermore, hydrocarbons cannot participate in a variety of noncovalent bonding interactions hydrogen bonds and in particular, electrostatic bonds. 

Other bases are also present in the DNA and RNA polymers, but to a much lesser extent. Examples include 5-methyl cytosine (present in the DNA of some plants and bacteria), 5-hydroxymethyl cytosine (present in the DNA of T-even phages bacterial viruses) and 4-thiouracil (present in some bacterial tRNA). 

It is possible to esterify a sugar hydroxyl with either phosphoric acid, pyrophosphoric acid or triphosphoric acid to give the nucleoside mono-, di-, or triphosphates, respectively. The example of adenosine triphosphate (ATP) has already been encountered. The combination of a base, sugar, and 

Base refers to a purine or a pyrimidine throughout this chapter 

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