This is a "Describe" question worth 6 marks, so you should aim to write a minimum of 6 points in your answer to get the full 6 marks.
Messenger RNA is produced in the nucleus of a cell by transcription. Firstly DNA Helicase (1) causes the DNA strands to separate by breaking hydrogen bonds (2). Then free RNA nucleotides are attracted to the exposed non-coding strand (3+4) and line up to it via complimentary base pairing (5). The enzyme RNA Polymerase then binds together the RNA nucleotides (6). Slicing then occurs removing the introns (7).