AQA Jan 2012 Paper 4 Q7

Answers available below

do not write outside the box the amino acids aspartic acid and phenylalanine react together to form a dipeptide this dipeptide can be converted into a methyl ester called aspartame h n c cooh h n ch cooh ch h o hh cooh h n cc o ch ch ch cooh aspartic acid phenylalanine aspartame aspartame has a sweet taste and is used in soft drinks and in sugar free foods for people with diabetes hydrolysis of aspartame forms methanol initially after a longer time the peptide link breaks to form the free amino acids neither of these amino acids tastes sweet a apart from the release of methanol suggest why aspartame is not used to sweeten foods that are to be cooked mark extra space b give the iupac name of aspartic acid mark c draw the organic species formed by aspartic acid at high ph mark wmp jan chem d draw the zwitterion of phenylalanine do not write outside the box mark e phenylalanine exists as a pair of stereoisomers e i state the meaning of the term stereoisomers marks e ii explain how a pair of stereoisomers can be distinguished marks extra space turn over wmp jan chem

Show answer