Under the genetic code, these RNA strands specify the sequence of amino acids within proteins in a process called translation. RNA strands are created using DNA strands as a template in a process called transcription, where DNA bases are exchanged for their corresponding bases except in the case of thymine (T), for which RNA substitutes uracil (U). It is the sequence of these four nucleobases along the backbone that encodes genetic information. Attached to each sugar is one of four types of nucleobases (or bases). The two strands of DNA run in opposite directions to each other and are thus antiparallel. A large part of DNA (more than 98% for humans) is non-coding, meaning that these sections do not serve as patterns for protein sequences. This information is replicated when the two strands separate.

In DNA, the pyrimidines are thymine and cytosine the purines are adenine and guanine.Д«oth strands of double-stranded DNA store the same biological information. The complementary nitrogenous bases are divided into two groups, pyrimidines and purines. The nitrogenous bases of the two separate polynucleotide strands are bound together, according to base pairing rules (A with T and C with G), with hydrogen bonds to make double-stranded DNA. The nucleotides are joined to one another in a chain by covalent bonds (known as the phospho-diester linkage) between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. Each nucleotide is composed of one of four nitrogen-containing nucleobases ( cytosine, guanine, adenine or thymine ), a sugar called deoxyribose, and a phosphate group. The two DNA strands are known as polynucleotides as they are composed of simpler monomeric units called nucleotides. Alongside proteins, lipids and complex carbohydrates ( polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life.

DNA and ribonucleic acid (RNA) are nucleic acids. Deoxyribonucleic acid ( / d iЛђ Л€ Й’ k s ЙЄ ЛЊ r aЙЄ b oКЉ nj uЛђ ЛЊ k l iЛђ ЙЄ k, - ЛЊ k l eЙЄ-/ ( listen) DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses.

1979 atc 70 parts