Question

A mutation within a gene that will insert a premature stop codon in mrna would ________. result in a longer polypeptide chain result in a shortened polypeptide chain change the location at which transcription of the next gene begins have the same effect as deleting a single nucleotide in the gene

Answer 1

The correct answer is "result in a shortened polypeptide chain".

This is a defect in the genetic code wherein the mRNA transcribed from the DNA has a premature stop codon. A stop codon is a codon (three nucleotides) which will signal the translation process to stop by a release factor. The stop codons for humans are UAA, UAG, and UGA. In the event where there is a mutation involving a premature stop codon in the mRNA, then the translation process will end prematurely making the elongating polypeptide chain to also release prematurely. This polypeptide chain is shortened as the elongation process is interrupted.

Answer 2

Answer:

Option B, result in a shortened polypeptide chain

Explanation:

Premature stop codon causes mutation which is called as non-sense mutation. In a non-sense mutation, the nonsense codon do not code for any amino acid instead they stop the coding and causes end of protein synthesis. Due to this, proteins are not synthesized to their full length and are also incomplete. These proteins are mostly nonfunctional, inactive and mutated.

Hence, option B is correct