Problem : What base in the following codon could be mutated to result in a nonsense mutation?

5'-U U G-3'

If the second base is changed from a U to an A, the resulting codon is 5'-UAG-3' which is a stop codon. Mutations that result in stop codons are called nonsense mutations.

Problem : Describe the difference between a base substitution mutation and an insertion/deletion mutation.

A base substitution involves the substitution of one nucleotide for another, and effects the coding of a single codon. An insertion/deletion mutation involves the addition of an extra nucleotide into a sequence or the removal of a nucleotide from a sequence. An insertion/deletion mutation can change the entire reading frame of a genetic sequence, affecting the coding of every codon in that sequence.

Problem : What type of mutation has occurred between the first and second base sequences?

1: 5'-AUGGACCAAUAU-3' 2: 5'-AUGGACAAUAU-3'

The mutation is a frameshift mutation from the deletion of a C.
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