Final answer:
The codons for valine, alanine, methionine, and threonine can be determined using codon tables, considering the type of mutation involved. If a single nucleotide is altered, the mutation could be silent, missense, or nonsense, affecting the protein differently.
Step-by-step explanation:
Codons are nucleotide triplets that specify amino acids during the process of protein synthesis. In a linked problem, it is assumed that mutations caused by a mutagen are single nucleotide changes, affecting the codons for specific amino acids at the affected site. The codons for the amino acids valine, alanine, methionine, and threonine can be deduced based on codon tables and knowledge of genetic mutations.
Valine is commonly represented by the codons GUU, GUC, GUA, and GUG. Alanine is encoded by the codons GCU, GCC, GCA, and GCG. Methionine, which is also the start codon for protein synthesis, is encoded by the codon AUG. Threonine is encoded by the codons ACU, ACC, ACA, and ACG.
If there is a point mutation, it may cause a silent mutation (no change in the amino acid), a missense mutation (a different amino acid is encoded), or a nonsense mutation (an amino acid is replaced by a stop codon). These kinds of mutations have varying effects on protein function, which ranges from negligible to rendering a protein nonfunctional.