Question

The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. This results in:__________

a) a base-pair substitution.
b) a nucleotide mismatch.
c) a frameshift mutation.
d) a polypeptide missing an amino acid.
e) a nonsense mutation.

Answer 1

d) a polypeptide missing an amino acid.

Step-by-step explanation:

Deletion is a type of mutation when one or more codons from the reading frame are removed. This results in the production of a relatively shorter mRNA that lacks one or more codons otherwise present in the non-mutated mRNA. When there is a deletion of a single codon in the gene for cystic fibrosis, the resultant shorter mRNA codes for a polypeptide chain that does not carry one amino acid. For example, deletion of one codon results in deletion of a Phe residue present at position 508 in CFTR. The mutated transmembrane protein CFTR folds in an improper way.