Question

If a mutation occurs in an mRNA codon that was originally ACA, which mutated mRNA codon would result in an amino acid sequence different from that produced by the ACA codon?

A) AGA
B) ACC
C) ACG
D) ACT

Answer 1

The mutated codon that would result in an amino acid sequence different from the original ACA is AGA, which encodes for the amino acid arginine instead of threonine.

Step-by-step explanation:

If a mutation occurs in an mRNA codon that was originally ACA, you are looking for a mutated codon that would result in a different amino acid than that produced by the ACA codon. The ACA codon codes for the amino acid threonine in the genetic code.

• AGA would change the amino acid to arginine.
• ACC still codes for threonine, so there is no change.
• ACG also codes for threonine, so there is no change.
• ACT codes for threonine as well, so again, there is no change.

Thus, the only mutated codon from the options provided that would result in an amino acid sequence different from that produced by the ACA codon is AGA, as it encodes the amino acid arginine, not threonine.