Becker's World of the Cell 9th Edition by Lewis Kleinsmith, Jeff Hardin, Gregory Paul Bertoni

Exercise 4

Amino Acid Substitutions in Mutant Proteins. Although the codon assignments summarized in Figure 21-7 were originally deduced from experiments involving synthetic RNA polymers and triplets, their validity was subsequently confirmed by examining the amino acid sequences of normally occurring mutant proteins. The table below lists some examples of amino acid substitutions seen in mutant forms of hemoglobin, tryptophan synthase, and the tobacco mosaic virus coat protein. For each amino acid alteration, list the corresponding single-base changes in mRNA that could have caused that particular amino acid substitution.