Question

Student A believes that a missense mutation would lead to a nonfunctioning protein. Student B believes that the insertion of 3 nucleotides would be more likely to lead to a nonfunctioning protein. Student C disagrees with both student A and B claiming that such mutations would not alter the function of the protein. WHos perspective is the most correct and why?

Answer 1

A nonsense mutation may be a mutation during a DNA sequence that leads to a shorter, unfinished protein product. DNA may be a chain of the many smaller molecules called nucleotides. During protein formation, DNA (or RNA) nucleotide sequences are read three nucleotides at a time in units called codons, and every codon corresponds to a selected aminoalkanoic acid or stop signal (stop codon). Stop codons also are called nonsense codons because they are doing not code for an aminoalkanoic acid and instead signal the top of protein synthesis. Thus, nonsense mutations occur when a premature nonsense or stop codon is introduced within the DNA sequence. When the mutated sequence is translated into a protein, the resulting protein is incomplete and shorter than normal. Consequently, most nonsense mutations end in nonfunctional proteins.

Missense mutation means change in one amino acid in a protein, arising from a point mutation in a single nucleotide AND it is a type of nonsynonymous substitution in a DNA sequence. Another type of nonsynonymous substitution is a nonsense mutation in which a codon is changed to a premature stop codon that results in truncation of the resulting protein. Missense mutations can resulting protein nonfunctional.

An insertion changes the number of DNA bases in a gene by adding a piece of DNA. As a result, the protein made by the gene may not function properly.

so student A is more correct