Genetic Code

A series of nucleotides makes up messenger RNA (mRNA), the template for protein synthesis. Each nucleotide contains one of four nitrogenous bases, Uracil, Cytosine, Adenine, and Guanine. Their order in a strand of mRNA specifies the order in which amino acids are added as a protein is built; every three nucleotides specifies one amino acid. This chart identifies each amino acid by its three-letter codon(s). For example, G under the “first letter” column, C under the “second letter” column, and A under the “third letter” column intersect at alanine, the amino acid specified by the sequence GCA. Most amino acids are identified by more than one codon (for instance, GCU, GCC, GCA, and GCG all code for alanine).

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Amino Acids

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