Since the mRNA is read as codons, how many nucleotides are in each codon?

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ncchemist eNotes educator| Certified Educator

mRNA stands for messenger RNA and it serves as the bridge between the two phases of protein biosynthesis.  In the transcription phase, a sequence of DNA unbinds and the sequence of nucleotides is used to make a complementary strand of messenger RNA.  The mRNA then exits the nucleus and goes to a ribosome for the translation phase, where the mRNA is converted to a polypeptide sequence of amino acids to make a new protein.  A codon refers to a sequence of three nucleotide that in turn codes for a specific amino acid.  In addition, there are stop and start codons which tell the ribosome to either start or stop a new polypeptide sequence.  So a codon is made up of three nucleotides.