Question

A genetic mutation that does not result in a change in the amino acid sequence of the resulting protein is called

A. a silent mutation
B. a nonsense mutation
C. a chromosomal mutation
D. a frame shift mutation

Answer 1

The answer is A.

You can remember this by thinking that since there was no change in the amino acid sequence, the mutation is silent in the fact that it didn't cause any trouble in the amino acid sequence.

Answer 2

A (Silent Mutation)

Step-by-step explanation:

From time to time, changes occur in the nucleotide sequences that makes up the genetic material (DNA). These changes whether big or small are referred to as MUTATION. The mutation can be restricted to one that affects only one nucleotide base in the sequence, this form is called POINT MUTATION.

Point mutation can affect the nucleotide sequence in the sense that a single nucleotide will either be deleted, substituted by another nucleotide, or another nucleotide be added or inserted. In the case of substitution, a nucleotide base replaces another in the sequence. This kind results in three types of mutation depending on the effect on the resulting polypeptide, they are: Silent Mutation, Missense Mutation, and Nonsense Mutation.

In the case of Missense and Nonsense Mutations, a different polypeptide and a non-functional polypeptide due to stop codon encountered is produced respectively.

For silent mutation, a nucleotide gets replaced by another but it does not change the polypeptide or protein eventually produced and hence, has no effect at all on the mutated organism. This is possible because of the DEGENERATE nature of the genetic code, in which more than one codon in the genetic sequence codes for one particular amino acid (protein building block). So if a nucleotide gets replaced, the nucleotide replacing it might also form a codon that encodes the same amino acid as the original codon.

Example is CODON UUC that encodes Phenylalanine, if the last nucleotide C, gets replaced by nucleotide U, it forms a UUU codon, which also encodes the same amino acid (Phenylalanine).