Describe how mRNA is produced within a cell

DNA is unwound by DNA helicase. This exposes the two strands of DNA, through the breaking of hydrogen bonds. This allows for complementary RNA nucleotides to join to one of the two strands - i.e. they are 'attracted' to the exposed bases. Consequently, RNA Polymerase will join together these free RNA nucleotides, and the RNA moves away from the free DNA strand. This pre-mRNA undergoes splicing, through the actions of the spliceosome, allowing for the removal of introns, or non-coding DNA; this action results in the production of mRNA.