 When a gene is read by a cell the DNA sequence is copied into a very similar molecule called RNA (this process is called transcription).Transcription is controlled by other DNA sequences (such as promoters), which show a cell where genes are, and control how often they are copied.The RNA copy made from a gene is then fed through a structure called a ribosome, which translates the sequence of nucleotides in the RNA into the correct sequence of amino acids and joins these amino acids together to make a complete protein chain.