Question

The effects of point mutations on polypeptides Point mutations are those that alter a single base pair or base location, and include substitutions and frameshift mutations. They can range in severity from no phenotypic change to complete loss of function. Rank the following point mutations in order of least damaging to most damaging if they occur in the middle of the coding sequence of a polypeptide.
Hints Reset Help
Missense Silent Nonsense Frameshift
Least damaging Most damaging

Answer 1

Answer:

The sequence from least damaging to most damaging is silent, missense, frameshift, and nonsense mutation.

Explanation:

A silent mutation refers to a modification in the sequence of nucleotide bases that constitutes DNA, however, it does not result in a substantial change in the amino acid or in the function of the entire protein. In missense mutation, one DNA nucleotide gets switched out with another one in a manner, which modifies the specified amino acid.  

When a missense mutation takes place in the molecule of DNA, it changes one of the sequences of RNA codon produced at the time of transcription. A frameshift mutation refers to a specific kind of mutation, which comprise either deletion or insertion of the additional bases of DNA. Following the mutation, the entire sequence of DNA will be read incorrectly.  

A nonsense mutation refers to a genetic mutation in the sequence of DNA, which leads to the formation of the shorter or unfinished protein product. This mutation takes place when an undeveloped nonsense or stop codon gets presented in the sequence of DNA.  

Thus, the silent mutation is the least damaging as it does not exhibit any influence on the function or composition of the protein. While nonsense mutation shows the most damaging effect as it results in an abrupt termination peptide chain.