Protein synthesis begins with the synthesis of messenger RNA molecules, which then move from the nucleus into the cytoplasm. In the cytoplasm, the strand of messenger RNA becomes associated with ribosomes.
Amino acids are carried to the ribosomes and messenger RNA by transfer RNAs.
The anticodons of the transfer RNAs align with the codons of the messenger RNA. The amino acids carried by the transfer RNAs bond together in a sequence determined by the base sequence of the messenger RNA.
The resulting chain of amino acids is a polypeptide. Some proteins consist of a single polypeptide chain, while others include two or more.
According to the one gene -- one polypeptide hypothesis, each gene controls the synthesis of a single polypeptide. A modern definition of the gene is the sequence of nucleotides in a DNA molecule necessary to synthesize a polypeptide.
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