Describe how mRNA is produced in the nucleus of a cell

Production of mRNA is called Transcription, which can be divided into 3 stages: Initiation, Elongation and Termination.Initiation: DNA Helicase (Enzyme) binds to a promoter region of DNA (a short section of bases at the beginning of a gene), The Helicase then begins to 'unzip' the double stranded DNA into 2 single strands.Elongation: 1 of the single DNA strands then serves as a template. Complementary nucleotides through the action of RNA polymerase will bind to the template strand forming a new mRNA molecule (polymerisation). For A levels focus on the idea that mRNA is synthesised from the 5' to 3' direction using only 1 of the DNA strands as a template. This is slightly different to DNA synthesis that uses both strands of DNA.Termination: Polymerisation continues until RNA polymerase reached a termination codon, 3 base pairs that tell the polymerase to stop adding nucleotides. The new pre-mRNA strand is then released from the DNA, where introns are excised to produce an mRNA with only the protein coding sections of DNA.