2. The genetic code and ribosomes

Figure 7a: Nucleobases on an mRNA strand

Figure 7a: Nucleobases on an mRNA strand

 Figure 7b: The corresponding codons, each encoding an amino acid

Figure 7b: The corresponding codons, each encoding an amino acid

2.1 Characteristics of the genetic code

Definitions

The genetic code is the set of rules used by living cells, by which information encoded within genetic material is translated into proteins.

This code is the link between the nucleobase sequence of messenger RNA (mRNA) and the amino acid sequence of the protein.

From 3 nucleotides forming 1 codon or triplet, the ribosome encodes 1 amino acid onto the protein.

Among the 64 available codons, 3 codons ( UAA, UAG, UGA) are triplets that cannot be translated into amino acids. These codons are termed nonsense (or stop/termination codons).