Transcription is when the DNA genetic code is copied by messenger R.N.A. The transcript consists of a series of codons or triplets as per the DNA template. The DNA remains in the nucleus. However, the mRNA can travel to the ribosome and attach its copied transcript so that it can be translated into the amino acid sequence of a polypeptide. This in turn will fold into a functional protein that is needed by the cell. Transfer RNA which is found in the cytoplasm carries the appropriate amino acid to the ribosome according to the messenger RNA transcript. As each amino acid joins to the next by a peptide bond, a polypeptide is formed. A stop message causes the polypeptide to detach from the ribosome and fold into a protein.