DNA transcription. Illustration of a strand of deoxyribonucleic acid (DNA, right) undergoing transcription to produce molecules of ribonucleic acid (RNA). Here, the DNA strand is being untwisted. The cell nucleus is at upper left, with proteins also visible. These nucleic acid fragments are part of the process used in the cellular synthesis of proteins. The production of RNA from DNA is carried out by enzyme complexes called RNA polymerase.