<P> In contrast, both RNA and proteins are normally single - stranded . Therefore, they are not constrained by the regular geometry of the DNA double helix, and so fold into complex three - dimensional shapes dependent on their sequence . These different shapes are responsible for many of the common properties of RNA and proteins, including the formation of specific binding pockets, and the ability to catalyse biochemical reactions . </P> <P> DNA is an information storage macromolecule that encodes the complete set of instructions (the genome) that are required to assemble, maintain, and reproduce every living organism . </P> <P> DNA and RNA are both capable of encoding genetic information, because there are biochemical mechanisms which read the information coded within a DNA or RNA sequence and use it to generate a specified protein . On the other hand, the sequence information of a protein molecule is not used by cells to functionally encode genetic information . </P> <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>

Which of the following is a basic principle of macromolecular assembly