The four-letter code; always use the chart reading the mRNA strand is called what?

• A. Genetic code
• B. Codon
• C. Nucleotide code
• D. Amino acid sequence

Answer: (A)

Reading the genetic information from mRNA uses a chart that maps each codon to an amino acid. This mapping is called the genetic code. The chart isn’t just about a single codon or the final product; it’s the whole set of rules that tells you which amino acid corresponds to every possible three-nucleotide sequence on mRNA. While a codon is the three-letter unit you read from the mRNA, the genetic code is the complete system that translates those codons into the amino acids that make up proteins. The amino acid sequence is what you end up with after applying the code, not the coding system itself. Nucleotide code isn’t a standard term for this translation, since the recognized term is the genetic code. For example, a codon like AUG signals the start and codes for methionine, illustrating how the code directs protein building.