I Below are the amino acid sequences of a short peptide hormone and three differ

Question

I Below are the amino acid sequences of a short peptide hormone and three different mutant versions of the same hormone. Use this sequence information to answer the questions below. Wild-type = Met-Trp-Tyr-Arg-Gly-Ser-Pro-Thr Mutant A = Met-Trp-His-Arg-Gly-Ser-Pro-Thr Mutant B = Met-Tm Mutant C = Met-Cys-Ile-Val-Val-Val-GIn-His a. Determine the exact nucleotide change in each of the three mutant gene sequences. b. There are 8 amino acids in this peptide, but there are 9 codons; what is the ninth codon doing? c. Researchers identify a fourth mutant (Mutant D). The resulting protein is identical to the wild-type in its sequence, but it produces far less of it than wild-type cells do. Describe where you think this mutation is likely to be.

Explanation / Answer

a. The exact nucleotide change in each of the mutant gene sequences will be:

Mutant A- The nucleotide at 7th place changed from uracil to cytosine

Mutant B- The nucleotide at 9th place changed to Adenine or guanine

Mutant C- The nucleotide at 6th place changed to uracil or cytosine

b. The 9th codon is acting like a stop codon. This codon does not translate into amino acid but rather terminates the translation process of peptide.

c. The mutation will be nonsense type of mutation where the cell sequence is signalled to stop protein production prematurely.

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.