<P> Proteins are functional macromolecules responsible for catalysing the biochemical reactions that sustain life . Proteins carry out all functions of an organism, for example photosynthesis, neural function, vision, and movement . </P> <P> The single - stranded nature of protein molecules, together with their composition of 20 or more different amino acid building blocks, allows them to fold in to a vast number of different three - dimensional shapes, while providing binding pockets through which they can specifically interact with all manner of molecules . In addition, the chemical diversity of the different amino acids, together with different chemical environments afforded by local 3D structure, enables many proteins to act as Enzymes, catalyzing a wide range of specific biochemical transformations within cells . In addition, proteins have evolved the ability to bind a wide range of cofactors and Coenzymes, smaller molecules that can endow the protein with specific activities beyond those associated with the polypeptide chain alone . </P> <P> RNA is multifunctional, its primary function is to encode proteins, according to the instructions within a cell's DNA . They control and regulate many aspects of protein synthesis in eukaryotes . </P> <P> RNA encodes genetic information that can be translated into the amino acid sequence of proteins, as evidenced by the messenger RNA molecules present within every cell, and the RNA genomes of a large number of viruses . The single - stranded nature of RNA, together with tendency for rapid breakdown and a lack of repair systems means that RNA is not so well suited for the long - term storage of genetic information as is DNA . </P>

The breakdown of giant molecules into repeating components is