Question

question 15
why can a frameshift mutation be harmful?
○ it removes introns
○ it only changes one amino acid
○ it changes the reading frame, altering all downstream amino acids
○ it adds a stop codon at the end

Explanation:

• Analyze each option:
• "It removes introns": Intron removal is part of RNA splicing, not related to frameshift mutation harm. Eliminate.
• "It only changes one amino acid": A frameshift mutation (insertion/deletion of non - multiple of 3 nucleotides) changes the reading frame, altering many amino acids, not just one. Eliminate.
• "It changes the reading frame, altering all downstream amino acids": Frameshift mutations shift the codon reading frame. This leads to a completely different sequence of amino acids downstream, often resulting in a non - functional protein, which is why it's harmful. This matches the concept.
• "It adds a stop codon at the end": Adding a stop codon at the end (like in some non - harmful or less harmful mutations) is not the main reason frameshift mutations are harmful. Frameshift mutations usually cause major disruptions in the amino acid sequence, not just adding a stop codon at the end. Eliminate.

Answer:

C. It changes the reading frame, altering all downstream amino acids (assuming the third option is labeled C; if the original labeling was different, adjust the label but keep the text. In the given options, the correct one is "It changes the reading frame, altering all downstream amino acids")