Nucleic acid sequence Nucleic acid sequence A nucleic acid sequence is a succession of letters that indicate the order of nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. By convention, sequences are usually presented from the 5' end to the 3' end. For DNA, the sense strand is used. Because nucleic acids are normally linear (unbranched) polymers, specifying the sequence is equivalent to defining the covalent structure of the entire molecule. For this reason, the nucleic acid sequence is also termed the primary structure. The sequence has capacity to represent information. Biological deoxyribonucleic acid represents the information which directs
Hexafluorosilicic acid Hexafluorosilicic acid Hexafluorosilicic acid is an inorganic compound with the chemical formula (also written as ). It is a colorless liquid rarely encountered undiluted. Hexafluorosilicic acid has a distinctive sour taste and pungent smell. It is produced naturally on a large scale in volcanoes. It is manufactured as a precursor to aluminum trifluoride and synthetic cryolite. It is commonly used as a source of fluoride for water fluoridation. Salts derived from hexafluorosilicic acid are called hexafluorosilicates. In aqueous solution, the hydronium cation (HO) is traditionally equated with a solvated proton, and as such, the formula for this compound is often