Final answer:
The genetic code is unambiguous and redundant, meaning each codon codes for a single amino acid or a start or stop signal—and most amino acids are encoded by multiple codons.
Step-by-step explanation:
The genetic code is not ambiguous, which means each codon codes for only one amino acid or a start/stop signal during the process of protein synthesis. This unambiguity ensures that there's no confusion about which amino acid the codon specifies. Furthermore, the genetic code is described as redundant because most amino acids are coded for by more than one codon. This redundancy helps to protect against errors in the synthesis of proteins. For example, the amino acid threonine is coded by four different codons, which helps prevent mistakes if a single base changes accidentally.
This idea of redundancy and lack of ambiguity is an important aspect of translation - the process by which the instructions carried in the mRNA are used to synthesize proteins. Specifically, the codon AUG is known as the initiation codon and is the starting point for protein synthesis, while three specific codons (UAA, UAG & UGA) are known as stop codons or nonsense codons, signaling the end of protein synthesis.
Each codon consists of three nucleotide bases in a row on an mRNA molecule, and its sequence determines the sequence of amino acids in the protein. The genetic code is universal, meaning that the same codons specify the same amino acids across nearly all living organisms, from viruses to humans. Thus, each one of the 64 possible codons corresponds to one of the twenty amino acids used in proteins or signifies a start or stop to the translation process.
Regarding the student's question, the correct answer is that the genetic code is not ambiguous because each codon codes for only one amino acid or a start or stop signal, not because any of the other reasons provided.