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1860 bronze farthing, depicting Britannia
Beginning in 1860, Britain replaced its copper coinage with bronze pieces. The existing copper coins (principally the penny , the halfpenny and the farthing ) were seen as too large and heavy. Thomas Graham , the master of the Mint , persuaded William Gladstone , the Chancellor of the Exchequer , to replace them. Gladstone secured authorising legislation and a vote of funds in Parliament . Leonard Charles Wyon of the Royal Mint was tasked with rendering designs for the new coinage. He produced an obverse for the new coins depicting Queen Victoria , who modelled for him. The reverse featured Britannia (pictured) . With the aid of two outside firms, the Royal Mint struck enough of the new bronze coins that it began calling in the copper pieces in 1861, a process complete after 1877, although less than half in terms of value of the extant coppers were paid in. The new coins remained current until the run-up to decimalisation in 1971 , except for the farthing, which was demonetised from 1 January 1961. (Full article... )
In chemistry , an amino acid is a molecule containing both amine and carboxyl functional groups . In biochemistry , this term refers to alpha-amino acids with the general formula H2 NCHRCOOH, where R is an organic substituent.[ 1] In the alpha amino acids, the amino and carboxylate groups are attached to the same carbon , which is called the α–carbon . The various alpha amino acids differ in which side chain (R group) is attached to their alpha carbon. They can vary in size from just a hydrogen atom in glycine through a methyl group in alanine to a large heterocyclic group in tryptophan .
Beyond the amino acids that are found in all forms of life , many non-natural amino acids have vital roles in technology and industry. For example, the chelating agents EDTA and nitrilotriacetic acid are alpha amino acids that are important in the chemical industry . (more... )
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^ Proline is an exception to this general formula. It lacks the NH2 group because of the cyclization of the side chain.