The first stage of proteinsynthesis is TRANSCRIPTION. The hydrogen bonds between the 2 DNA strands in the gene break apart. The DNA molecule uncoils. One strand is used as a template to make an RNA copy. Called mRNA. free RNA mononuleotides line up on the template strand. RNA mononucleotides pair up with complementary bases. An mRNA molecule is formed. mRNA moves out of the nucleus through a nuclear pore. The mRNA attaches itself to a ribosome in the cytoplasm.

The second stage of proteinsynthesis is TRANSLATION. mRNA attaches itself to a ribosome and transfer RNA (tRNA) which carry amino acids to the ribosome. tRNA attaches itself to mRNA by complementary base pairing. Second tRNA attaches to the next triplet of bases on the mRNA. Third tRNA binds to the next triplet on the mRNA. It's amino acid binds to the first two and the 2nd tRNA molecule moves away. The process continues making a chain of linked amino acids (polypeptide chain) until a STOP signal on the mRNA molecule. The polypeptide chain than moves away from the ribosome.

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