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

Answer 1

Question from alternative source

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

Answer:

Nonsense

Explanation:

Nonsense mutations describe mutations that produce a premature stop codon. The stop codons are UAG, UAA, and UGA. A way in which this could arise is, for example, if there was a substution of a nucleotide in the mRNA codon UAC (which codes for the amino acid Tyrosine) to the nucleotide UAG (which codes for a stop codon).

The translation machinery would reach this codon, which signals that translation should be terminated. This would mean that the mRNA would be released, and a truncated (shortened) version of the amino acid would be produced. This is likely to be non-functional, and may even be marked for destruction by the cell.