Describe the process of transcription in detail (6 marks)

Transcription is the process by which a section of DNA acts as a template for the creation of a complementary mRNA strand. mRNA is needed for the creation of a polypeptide.
An enzyme called DNA helicase binds to a complementary start codon on the DNA and brakes the H bonds causing the DNA to unwind, exposing its bases.
Each exposed DNA base binds to a complementary free-floating RNA nucleotide (Cytosine with Guanine, and Uracil (replacing Thymine) with Adenine).
Another enzyme called RNA Polymerase moves along the DNA strand causing H bonds to form between the RNA bases to make a strand of RNA nucleotides. As polymerase moves along the DNA, the DNA Double Helix reforms behind the enzyme. DNA Polymerase detaches once it reaches a stop codon.
The new complementary strand of RNA bases formed from the DNA is called pre-mRNA and it detaches from the DNA.However, Pre-mRNA is too large to fit through the nuclear pore and leave the nucleus, therefore splicing takes place, to remove the non-coding introns, leaving behind the important exons. The mRNA is attracted to the ribosome in the cytoplasm, ready for translation to take place.