Final answer:
The statement is false; a nucleotide substitution can affect the protein's function, as amino acid sequences determine protein structure and a single change can influence this. Substitution mutations can lead to changes in the amino acid sequence, while an insertion of nucleotides can disrupt protein function if it affects a functional domain.
Step-by-step explanation:
The statement that the substitution of one nucleotide for another in the gene never affects the function of the protein is false. If a mutation in a gene causes a different amino acid to be encoded, it can affect the protein's function. This is because the structure of proteins is determined by the sequence of amino acids, and even a single change can alter the protein's shape and function. For instance, a substitution mutation can lead to a missense mutation where a different amino acid is placed, potentially affecting the protein's function. Alternatively, a nonsense mutation can create a premature stop codon, halting protein synthesis, which could result in a truncated, non-functional protein.
Regarding the codon chart question, a single nucleotide change in the given DNA sequence can lead to a variation in the protein produced. Amino acids are encoded by codons; therefore, a change in one nucleotide could modify which amino acid is integrated into the protein, potentially affecting its function. Additionally, not all nucleotide changes affect the phenotype because of a concept known as redundancy in the genetic code, where multiple codons can encode the same amino acid (silent mutation). An insertion of three nucleotides may not produce a shorter protein if these nucleotides form a complete codon that adds one amino acid to the protein; however, if the insertion interrupts a functional domain within the protein, it can still disrupt the protein's function.