Biochemistry 4th Edition by Reginald Garrett, Charles Grisham

Exercise 17

Suppose in the Figure 12.8 known amino acid sequence, tryptophan was replaced by cysteine.
How would that affect the possible mRNA sequence (Consult the inside front cover of this textbook for amino acid codons.) How many nucleotide changes are necessary in replacing Trp with Cys in this coding sequence What is the total number of possible oligonucleotide sequences for the mRNA if Cys replaces Trp