Which mutation could lead to a loss of protein function if left unrepaired?

Which mutation could lead to a loss of protein function if left unrepaired?

• A. A mutation that shifts the protein reading frame from frame 1 to frame 2
• B. A mutation changing TAA codon to TAG codon
• C. All of the choices given
• D. None of the choices given

Answer: (A)

A mutation that shifts the protein reading frame from frame 1 to frame 2 is likely to lead to a loss of protein function because it disrupts the entire sequence of amino acids that are produced during translation. This type of mutation, known as a frameshift mutation, occurs when insertions or deletions of nucleotides lead to a change in the way the sequence of codons is read. Since codons are read in groups of three nucleotides, altering the reading frame changes all subsequent codons downstream, resulting in a completely different and often nonfunctional protein being produced. In the context of the other options, a mutation changing a TAA codon to a TAG codon represents a change in one stop codon to another stop codon, which may not necessarily result in a loss of protein function if the protein synthesis terminates correctly. Therefore, while both mutations can be detrimental, the frameshift clearly stands out as a more direct cause of misfolding or loss of functional protein due to the extensive alteration of the entire protein coding sequence. The choice that includes all or none does not specifically address the significant impact of a frameshift mutation on protein function as compared to the other mutations presented.

A mutation that shifts the protein reading frame from frame 1 to frame 2 is likely to lead to a loss of protein function because it disrupts the entire sequence of amino acids that are produced during translation. This type of mutation, known as a frameshift mutation, occurs when insertions or deletions of nucleotides lead to a change in the way the sequence of codons is read. Since codons are read in groups of three nucleotides, altering the reading frame changes all subsequent codons downstream, resulting in a completely different and often nonfunctional protein being produced.

In the context of the other options, a mutation changing a TAA codon to a TAG codon represents a change in one stop codon to another stop codon, which may not necessarily result in a loss of protein function if the protein synthesis terminates correctly. Therefore, while both mutations can be detrimental, the frameshift clearly stands out as a more direct cause of misfolding or loss of functional protein due to the extensive alteration of the entire protein coding sequence. The choice that includes all or none does not specifically address the significant impact of a frameshift mutation on protein function as compared to the other mutations presented.