8 - Nucleic Acids and Proteins

Abstract

This chapter summarizes the properties of nucleic acids and proteins, with a special emphasis on some of the plant-specific aspects. Nucleic acids and proteins are two major constituents of all living cells with critical roles. There are two types of nucleic acid in living organisms: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA and RNA are long polymers of subunits called nucleotides that are composed of a 5-carbon sugar backbone with one or more phosphate groups attached at the C-5 position. In addition, nitrogen-containing bases called purines and pyrimidines are also attached to the C-1 position of the sugar. Nucleotides for DNA contain a hydrogen atom at the C-2 position whereas those for RNA contain a hydroxyl group instead. Nucleic acids contain the information necessary for the synthesis of proteins with specific structures and functions. On the other hand, proteins are needed for the metabolism of nucleic acids in addition to performing practically all the enzymic reactions in a living cell. This chapter explains the biochemistry and detailed properties of DNA, RNA, and proteins. Cellular dynamics of DNA structure and organization is explained. The chapter also discusses the biosynthesis of nucleotides in detail.