<P> DNA has three primary attributes that allow it to be far better than RNA at encoding genetic information . First, it is normally double - stranded, so that there are a minimum of two copies of the information encoding each gene in every cell . Second, DNA has a much greater stability against breakdown than does RNA, an attribute primarily associated with the absence of the 2' - hydroxyl group within every nucleotide of DNA . Third, highly sophisticated DNA surveillance and repair systems are present which monitor damage to the DNA and repair the sequence when necessary . Analogous systems have not evolved for repairing damaged RNA molecules . Consequently, chromosomes can contain many billions of atoms, arranged in a specific chemical structure . </P> <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>

Enzymes are an example of which type of macromolecule