Question

A strain of mutant bacteria has been isolated. You isolate the mRNA corresponding to the mutated gene from this bacterial strain to use in an in vitro translation system and note that even in vitro it is difficult to use this message and obtain protein. Of the following, which is a likely explanation for these results?

A) There may be a mutation in the Shine-Dalgarno sequence of the DNA, resulting in mRNA that binds poorly to the ribosome.
B) There may be a mutation in the ribosomal rRNA recognizing the Shine-Dalgarno sequence of the message.
C) This mutant may have altered tRNA molecules, such that the codon-anticodon interaction during translation is affected.
D) This mutant may not manufacture enough translation factors for effective translation.
E) In this mutant, the ribosomal subunits may not associate well enough for effective translation.

Answer 1

The most likely explanation for the difficulty in obtaining protein from the mutant mRNA in an in vitro translation system is that the mutant bacteria may have altered tRNA molecules, which affects the codon-anticodon interaction during translation.

Step-by-step explanation:

The difficulty in obtaining protein from the mutant mRNA in an in vitro translation system could be explained by multiple factors. In this case, the most likely explanation would be option C: This mutant may have altered tRNA molecules, such that the codon-anticodon interaction during translation is affected.

To elaborate, tRNA molecules play a crucial role in translation as they carry the correct amino acids that match the codons on the mRNA strand. If the mutant bacteria have altered tRNA molecules, the codon-anticodon interaction may be affected, impairing translation and making it difficult to obtain protein in an in vitro system.

Options A, B, D, and E are less likely explanations. Mutations in the Shine-Dalgarno sequence of DNA (option A) and ribosomal rRNA recognizing the Shine-Dalgarno sequence (option B) would affect the binding of the mRNA to the ribosome, but they would not directly explain the difficulty in obtaining protein. Similarly, a deficiency in translation factors (option D) or inadequate association of ribosomal subunits (option E) would affect translation overall, not specifically for the mutant mRNA.