DNA (deoxyribose nucleic acid) or deoxyribonucleic acid is the molecular carrier of genetic information in living organisms and viruses. DNA carries the information translate into a form phe- notype in our body through the synthesis of proteins.
DNA in eukaryotic cells found in the core (nucleus), mito- chondria, and plastids. DNA in the cell nucleus called nuclear DNA, called mtDNA in mitochondria ( mitochondrial DNA or DNAmt / mitochondrial DNA ), whereas in plastids called plastids with DNA (DNA plastids). Meanwhile, prokaryotic organisms store DNA in nukleoid and also in the form of plasmid DNA. Prokaryotic DNA is not protected by a membrane as in the eukaryotic. DNA is polinukleotida (poly: many + nucleotides). Nucleotide is a unit composed of three compo- nents, namely sugar, phosphate, and nitrogen bases.
Structure of DNA-shaped double chains similar to the spiral staircase (double helix or double helix). The chain is composed of the first chain and the chain of complement. DNA double chain has an antiparallel arrangement. At the DNA chain, there are the 3 'and 5'. The 3 'end is the end of the ended with the OH group on carbon number 3 of the sugar, whereas the 5' end is the end of the DNA chain with the last OH group is at carbon atom number 5 of the sugar. One chain on the DNA has a direction 5 '- 3', while its complement chain has a direction of 3 '- 5'.