Final answer:
Having multiple codons for most amino acids offers a level of protection against mutations by allowing a single amino acid to be coded by different codons, reducing the chance that a mutation leads to a nonfunctional protein.
Step-by-step explanation:
The benefit of having multiple codons for all amino acids besides the start codon is mainly the redundancy of the genetic code, which is also known as degeneracy. This redundancy means that most amino acids are encoded by more than one codon, which helps to reduce the negative impact of random mutations on protein synthesis.
For instance, threonine is encoded by four different codons (ACU, ACC, ACA, and ACG), and this redundancy ensures that even if a mutation affects one nucleotide, especially in the third "wobble" position of the codon, the same amino acid may still be incorporated into the protein.
Furthermore, amino acids with chemically similar side chains are encoded by similar codons, which contributes to minimizing the effect of mutations on the protein's function.
The redundancy in the genetic code provides a measure of error tolerance, protecting against the consequences of mutations that may otherwise lead to the production of dysfunctional proteins.