Question

99. Changing a codon from GUU to __________ will NOT result in a phenotypic change for the organism.

A) GUC
B) CUU
C) CAA
D) GCU
E) CCG

Answer 1

A) GUC

Step-by-step explanation:

Some amino acids are encoded by more than one triplet codons. The genetic codes GUU, GUC, GUA, and GUG code for amino acid valine. Since these four genetic codes represent the same amino acid, replacing any one of them with others would not affect the encoded protein.

When a mutation changes the genetic code "GUU" into "GUC", there will not be any change in the encoded amino acid (both code for valine). So, this particular mutation would not cause any change in the respective protein and the genetic trait of the organism.