Gene expression can be described as the conversion of information from genes into messenger RNA through transcription. Transcription occurs in the nucleus and is where RNA copies of DNA are made. This process is facilitated by RNA polymerase, where an RNA nucleotide is added to an RNA strand. RNA polymerase is an enzyme used to produce transcribed RNA. It is responsible for building RNA chains, in the process previously described as transcription. RNA polymerase polymerizes ribonucleotides and the 3' end of RNA transcription. It is essential for life and is found in all organisms. It also unwinds the DNA molecule, using it as a template, before synthesizing the corresponding mRNA strands. mRNA, or messenger RNA, is part of a large group of RNA molecules that communicate information from DNA to ribosomes. The mRNA contains adenine, uracil, guanine and cytosine. DNA alternative that contains thymine instead of uracil. Ribosomes are part of a larger molecular group and represent the central location where transcription occurs. These ribosomes are responsible for connecting each other...