What is the effect of a nonsense mutation in a gene?

Question

A) It changes an amino acid in the encoded protein

B) It has no effect on the amino acid sequence of the encoded protein

C) It introduces a stop condon into the mRNA

D) It alters the reading frame of the mRNA

E) It prevents introns from being expressed

Answer 1

With a nonsense mutation, the new nucleotide changes a codon that specified an amino acid to one of the STOP codons (TAA, TAG, or TGA). Therefore, translation of the messenger RNA transcribed from this mutant gene will stop prematurely. The earlier in the gene that this occurs, the more truncated the protein product and the more likely that it will be unable to function.

The answer is C.

Answer 2

c