SAQ: Consider the structure (at physiological pH 7.4 ) of the following molecules and then answer the questions below. Serine, Threonine, Isoleucine, Tyrosine Explain how these molecules are similar and the importance of this when such molecules bind together to form a polymer. One of these molecules has a key structural difference, relative to the others. Name the molecule that is the ‘odd one out’ and describe the key structural difference.