What is a genetic code?


  1. Codon is the 3 letter sequence of DNA that instructs an amino acid to be added to the growing protein chain. Each of the 64 possible codes, consisting of AA and UU, are spaced out at equal distances along the gene. A gene is made up of many codons and the genetic code is written in uracil instead of thymine. Each gene has a specific combination of AA and UU which is what gives the gene its function. Some amino acids might have a similar codon so a certain gene might have different functions depending on the location of CA in the gene. Many of the codons have been identified but some of the non-coding regions have not.


    • GCC (Guanine–Cytosine-Cytosine) → alanine.
    • GUU (Guanine-Uracil-Uracil) → valine.
    • CUA (Cytosine-Uracil-Adenine) → leucine.
    • UCA (Uracil-Cytosine-Adenine) → serine
  2. Codon is a set of three nucleotides(triplets) in mRNA, functioning as a unit of genetic coding by specifying a particular amino acid during the synthesis of polypeptides/proteins in a cell. The genetic code comprises 64 such triplets of nucleotides that code for twenty amino acids.

    A codon specifies a transfer RNA carrying a specific amino acid, which is incorporated into a polypeptide chain during protein synthesis. The specificity for translating genetic information from DNA into mRNA, then to protein, is provided by codon-anticodon pairing.

    Sixty-one codons encode the 20 amino acids, leading to codon redundancy, and three codons signal the termination of polypeptide synthesis. The initiating codon is AUG/ATG which codes for methionine. UAA/TAA, UGA/TGA, and UAG/TAG are the terminating codons.

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