With no mutation, an mRNA sequence reads "UCA," which codes for serine. A mutation arises that changes the sequence to "UCC," which codes for serine. This is an example of all of the following types of mutation EXCEPT
A) point mutation.
B) synonynous mutation.
C) transversion.
D) nonsense mutation.

Question

Quizplus · Accepted Answer

The mutation from "UCA" to "UCC" is a point mutation because it involves a change in a single nucleotide. It is synonymous because the change does not alter the amino acid that is coded for (both code for serine). However, it is not a transversion (which involves a change between a purine and a pyrimidine or vice versa) but rather a transition (a change between two pyrimidines or two purines). Finally, it is not a nonsense mutation because it does not create a stop codon but instead codes for the same amino acid, serine.

With No Mutation, an MRNA Sequence Reads "UCA," Which Codes