Final answer:
The first step in decoding genetic messages is transcription, where genetic instructions from DNA are transcribed to mRNA, which then serves as a template for protein synthesis. The mRNA comprises sequences of codons, each representing an amino acid or signaling the start or termination of translation.
Step-by-step explanation:
Decoding the Genetic Code
The first step in decoding genetic messages is transcription. This is essential in the process whereby cells synthesize proteins based on the genetic information encoded in DNA. During transcription, the genetic instructions in DNA are copied to messenger RNA (mRNA). The mRNA then serves as a template for protein synthesis. The sequence of nitrogen bases, namely adenine (A), cytosine (C), guanine (G), and uracil (U), forms the genetic code in the mRNA chain. This code is read in sets of three bases, known as codons, with each codon representing an amino acid or a start/stop signal.
The initiation of transcription begins with the binding of RNA polymerase to the DNA at a specific location known as the promoter. The enzyme then unwinds the DNA and begins transcribing RNA from the template strand. AUG is the start codon, which establishes the reading frame for subsequent codons to be translated during the protein synthesis process. Transcription includes three main steps: initiation, elongation, and termination, resulting in a precursor mRNA strand that is further processed before it exits the nucleus.
The genetic code is notable for being universal, unambiguous, and redundant; every living organism uses it to translate genetic information into proteins. The universality of the genetic code means that, for most codons, the same amino acids are produced in all organisms.