Shown here are the amino acid sequences of the wild-type and three mutant forms of a short...

Shown here are the amino acid sequences of the wild-type and three mutant forms of a short protein. Use this information to answer the following questions:

(a) Using Figure, predict the type of mutation that led to each altered protein.

---

(b) For each mutant protein, determine the specific ribonucleotide change that led to its synthesis.

---

(c) The wild-type RNA consists of nine triplets. What is the role of the ninth triplet?

---

(d) Of the first eight wild-type triplets, which, if any, can you determine specifically from an analysis of the mutant proteins? In each case, explain why or why not.

---

(e) Another mutation (Mutant 4) is isolated. Its amino acid sequence is unchanged, but the mutant cells produce abnormally low amounts of the wild-type proteins. As specifically as you can, predict where this mutation exists in the gene.

Figure

The coding dictionary. AUG encodes methionine, which initiates most polypeptide chains. All other amino acids except tryptophan, which is encoded only by UGG, are represented by two to six triplets. The triplets UAA, UAG, and UGA are termination signals and do not encode any amino acids.