<P> The two strands of DNA run in opposite directions to each other and are thus antiparallel . Attached to each sugar is one of four types of nucleobases (informally, bases). It is the sequence of these four nucleobases along the backbone that encodes biological information . RNA strands are created using DNA strands as a template in a process called transcription . Under the genetic code, these RNA strands are translated to specify the sequence of amino acids within proteins in a process called translation . </P> <P> Within eukaryotic cells DNA is organized into long structures called chromosomes . During cell division these chromosomes are duplicated in the process of DNA replication, providing each cell its own complete set of chromosomes . Eukaryotic organisms (animals, plants, fungi and protists) store most of their DNA inside the cell nucleus and some of their DNA in organelles, such as mitochondria or chloroplasts . In contrast prokaryotes (bacteria and archaea) store their DNA only in the cytoplasm . Within the eukaryotic chromosomes, chromatin proteins such as histones compact and organize DNA . These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed . </P> <P> DNA was first isolated by Friedrich Miescher in 1869 . Its molecular structure was first identified by James Watson and Francis Crick at the Cavendish Laboratory within the University of Cambridge in 1953, whose model - building efforts were guided by X-ray diffraction data acquired by Raymond Gosling, who was a post-graduate student of Rosalind Franklin . DNA is used by researchers as a molecular tool to explore physical laws and theories, such as the ergodic theorem and the theory of elasticity . The unique material properties of DNA have made it an attractive molecule for material scientists and engineers interested in micro - and nano - fabrication . Among notable advances in this field are DNA origami and DNA - based hybrid materials . </P> <P> DNA is a long polymer made from repeating units called nucleotides . The structure of DNA is dynamic along its length, being capable of coiling into tight loops, and other shapes . In all species it is composed of two helical chains, bound to each other by hydrogen bonds . Both chains are coiled round the same axis, and have the same pitch of 34 ångströms (3.4 nanometres). The pair of chains has a radius of 10 ångströms (1.0 nanometre). According to another study, when measured in a different solution, the DNA chain measured 22 to 26 ångströms wide (2.2 to 2.6 nanometres), and one nucleotide unit measured 3.3 Å (0.33 nm) long . Although each individual nucleotide repeating unit is very small, DNA polymers can be very large molecules containing millions to hundreds of millions of nucleotides . For instance, the DNA in the largest human chromosome, chromosome number 1, consists of approximately 220 million base pairs and would be 85 mm long if straightened . </P>

Who discovered the basic structure of dna nucleotides