ISOLATION AND CHARACTERIZATION OF NUCLEIC ACIDS
Jan Eric C. Balete, Dorinne P. Barretto, Divine Trisha Angela T. Batac, Neill Steven C. Cachuela, Karel D. Cartagena
2C Medical Technology Biochemistry Laboratory
Nucleic acids are informational molecules with their primary structure containing a code or set of directions by which they can duplicate themselves and guide the synthesis of proteins.  They are very large molecules built from subunits called nucleotides. All nucleotides have a common structure: a phosphate group linked by a phosphodiester bond to a pentose (a five-carbon sugar molecule) that in turn is linked to an organic base. 
Figure 1. General structure of a nucleotide
One type of nucleic acid is the ribonucleic acid (RNA). The RNA is single-stranded used for the coding of the primary sequence of amino acids to make proteins, and is found mainly in the cytoplasm. In terms of structure, its distinguishing characteristic is that, from its name, ribonucleic acid indicates the presence of ribose, a cyclic monosaccharide with an aldehyde functional group. Furthermore, RNA can also be differentiated from other nucleic acids in terms of organic or nitrogen-containing bases. There are five organic bases involved in the formation of nucleic acids, and they could be categorized as purines and pyrimidines. The two-carbon nitrogen ring bases, such as adenine and guanine, are purines, while the one-carbon nitrogen ring bases, such as uracil, thymine and cytosine, are pyrimidines. 
Figure 2. Structure of purines and pyrimidines.
These bases are important because their sequencing is the way the information is stored. Each base is paired with a complimentary base through a hydrogen bond. In RNA, cytosine is paired with guanine (C-G) while adenine is paired with uracil (A-U). There are 3 major classes of RNA: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA)....
References:  http://chemwiki.ucdavis.edu/Biological_Chemistry/Nucleic_Acids
 Lodish H, Berk A, Zipursky SL, et al. Structure of Nucleic Acids. Molecular Cell Biology. 4th edition.
New York: W. H. Freeman; 2000.
Please join StudyMode to read the full document