Author: Nathan Lampson
This lesson will introduce codons, and describe how they are used in protein synthesis.
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RNA is a blueprint used to produce proteins in cells.  A strand of RNA is composed of a string of nucleotides.  Nucleotides are molecules that are like the words in a book -- when they are put together in the right order, they make a story.  

Each group of three nucleotides in an RNA strand are known as a codon.  The purpose of each codon is to provide the code for a single amino acid.  When the right group of amino acids are formed in a sequence they fold into a protein.  Codons that signal the start of a protein are known as a start codon.  When all of the amino acids that are needed for a protein are accounted for, a stop codon signals the ending of an amino acid chain that will form a protein.