MRNA is made during the first step of protein synthesis, which is transcription. The DNA's genetic information, or secret code, gets written onto a strand of mRNA. Transcription takes place in the nucleus. The next step in making a protein is called translation. The mRNA attaches itself to the ribosome.  Read more at: http://www.ducksters.com/science/biology/proteins_and_amino_acids.php This text is Copyright    Ducksters. Do not use without permission. The ribosome figures out where to start on the mRNA by finding a special three letter "begin" sequence called a codon. The ribosome then moves down the strand of mRNA. When the ribosome sees the "stop" code, it ends the translation and the protein is complete. 
How are proteins synthesized in a cell?