What type of point mutation leads to the introduction of a stop codon in mRNA sequence?

Question

BlackTom AI · Accepted Answer

First, let's restate the question for clarity: What type of point mutation leads to the introduction of a stop codon in the mRNA sequence?

Option 1: Missense. A missense mutation changes a single nucleotide so that one amino acid is replaced by a different one. While this alters the protein sequence, it does not inherently create a premature stop codon; its primary effect is at the level of amino acid substitution rather than termination.

Option 2: Frameshift. Frameshift mutations result from insertions or deletions that are not in multiples of three. They shift the reading frame of the entire downstream sequence, often creating a premature stop codon along the way, but the key characteristic is a shift in the reading frame rather than a single nucleotide substitution to a stop. It can lead to a stop codon, but this mutation type is defined by changing the reading frame, not by directly introducing a stop codon per se.

Option 3: Silent. Silent mutations alter the DNA sequence without changing the amino acid sequence of the resulting protein. This occurs due to redundancy in the genetic code, so no stop codon is introduced and protein function remains unchanged in terms of primary structure.

Option 4: Nonsense. A nonsense mutation is a single-nucleotide change that converts a codon encoding an amino acid into a stop codon, causing premature termination of translation. This directly matches the description of introducing a stop codon in the mRNA sequence.

In evaluating the options, consider the defining features of each mutation type. Missense changes amino acid identity but not termination; silent leaves the amino acid unchanged; frameshift alters the reading frame and can lead to early termination but the hallmark is frame disruption rather than a direct stop codon creation; the one that specifically creates a stop signal in the encoded protein is the nonsense mutation. The distinction hinges on whether the mutation directly creates a stop codon or affects reading frame rather than termination at a single codon.

Therefore, when focusing on the mechanism that introduces a stop codon directly, the option describing that exact effect aligns with the concept of a nonsense mutation.

AGRI10051_2025_SM2 Supplementary or Special Exam: Genetics for Agriculture (AGRI10051_2025_SM2)- Requires Respondus LockDown Browser

What type of point mutation leads to the introduction of a stop codon in mRNA sequence?

View Explanation

Log in for full answers

Similar Questions

Production of truncated proteins is commonly caused by which type of mutation?

A _________ mutation changes a codon that specifies an amino acid into one that terminates translation.

What type of point mutation leads to the introduction of a stop codon in mRNA sequence?

What is the result of a nonsense mutation in a coding sequence?

In a consumer society, many adults channel creativity into buying things

Economic stress and unpredictable times have resulted in a booming industry for self-help products

People born without creativity never can develop it

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler