Question 3 (1+2-3pts) A strain of yeast translates mRNA into protein inaccuratel

Question

Question 3 (1+2-3pts) A strain of yeast translates mRNA into protein inaccurately. Individual molecules of a particular protein isolated from this yeast have variations in the first 11 amino acids compared with the sequence of the same protein isolated from normal yeast cells, as listed in Figure. What is the most likely cause of this variation in protein sequence? normal sequence Met Thr Ala Ile Val Ser Asn Thr Gln Ile Lys variants Met Thr Ala Ala Val Ser Asn Thr Gln Ile Lys Met Thr Ala Gly Val Ser Asn Thr Gln Ile Lys Met Thr Ala Val Val Ser Asn Thr Gln Ile Lys Met Thr Ala Ile Val Ser Asn Thr Gln Ala Lys Met Thr Ala Ile Val Ser Asn Thr Gln Gly Lys Met Thr Ala Ile Val Ser Asn Thr Gln Val Lys (a) mutation in the DNA coding for the protein (b) a mutation in the anticodon of the isoleucine-tRNA (tRNA"e) (c) a mutation in the isoleucyl-tRNA synthetase that decreases its ability to distinguish between different amino acids (d) a mutation in the isoleucyl-tRNA synthetase that decreases its ability to distinguish between different tRNA molecules For any of the options you did not pick predict what the resulting variants of that mutation would look like. Option Prediction:

Explanation / Answer

The choice C seems most correct explanation for onset of mutational changes in this yeast.

Prediction: According to the information, there is a change in amino acid sequence of the yeast. The amino acid sequenced from the coding strand of the mutant yeast show that the initiation codon has been preserved. Also, it can be seen from the normal sequence and the mutated sequences that there occurs change of isoleucine amino acid with alanine, glycine or valine amino acids. This type of mutation is conservative in nature and does not alter the structure or function of the protein itself. However, since amino-acyl tRNA synthetase has enoromous specificity for amino acid isoleucine and its relative nucleotide codon, its specificity will be reduced for the corresponding trinucleotide codon sequences for valine, alanine or glycine.

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

---

---

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