Question

many different types of mutations can occur within the body. cystic fibrosis is a genetic disorder that is caused by different mutations within the cftr gene. one mutation in the cftr gene that leads to cystic fibrosis causes translation to end earlier in the gene sequence. which type of mutation causes this translation error that leads to cystic fibrosis?

○ silent
○ missense
○ nonsense
○ deletion

Explanation:

To determine the mutation type, we analyze each option:

• Silent mutation: Does not change the amino acid, so translation isn't shortened. Eliminate.
• Missense mutation: Changes one amino acid, but doesn't stop translation early. Eliminate.
• Nonsense mutation: Introduces a premature stop codon, causing translation to end early. This matches the description.
• Deletion: Involves removing nucleotides, but the key here is the early stop in translation, which is characteristic of nonsense, not just deletion (deletion can cause frameshift, but the question specifies a stop in translation timing, which is nonsense's key feature).

Answer:

C. nonsense