The pascal (symbol: Pa) is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength. It is defined as one newton per square metre. It is named after the French polymath Blaise Pascal.
Wikipedia English The Free Encyclopedia. Organophosphate. An organophosphate (sometimes abbreviated OP) or phosphate ester is the general name for esters of phosphoric acid. Many of the most important biochemicals are organophosphates, including DNA and RNA, as well as many of the cofactors essential for life. Organophosphates are the basis of many insecticides, herbicides, and nerve agents.
Ester Definition. An ester is an organic compound where the hydrogen in the compound's carboxyl group is replaced with a hydrocarbon group. Esters are derived from carboxylic acids and (usually) an alcohol. While carboxylic acid has the -COOH group, the hydrogen is replaced by a hydrocarbon in an ester.