Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original State the general formula for an α-amino acid as RCH(NH 2 )COOH. State that an amino acid exists as a zwitterion at a pH value called the isoelectric point. State that different R– groups in α-amino acids may result in different isoelectric points. Describe the acid–base properties of α-amino acids at different pH values.

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original General formula of an α-amino acid

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Structures of some amino acids

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Formation of a zwitterion from glycine

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Acid–base reactions of an amino acid

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Explain the formation of a peptide (amide) linkage between α-amino acids to form polypeptides and proteins. Describe the acid and alkaline hydrolysis of proteins and peptides to form α- amino acids or carboxylates.

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Formation of a dipeptide between glycine and alanine

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Alternative reaction of alanine and glycine

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Section of a polypeptide showing four different amino acids

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Acid hydrolysis of a dipeptide

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Alkaline hydrolysis of a polypeptide chain

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Describe optical isomers as non-superimposable mirror images about an organic chiral centre. Identify chiral centres in a molecule of given structural formula. Explain that optical isomerism and E/Z isomerism are types of stereoisomerism.

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original E and Z isomers of but-2-ene

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original The butan-2-ol molecule has a chiral carbon

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Optical isomers of CH 3 CH 2 CH(NH 2 )CH 3

Week 7 © Pearson Education Ltd 2009 This document may have been altered from the original Simplified three-dimensional representation of two optical isomers