Transcription (Synthesis of RNA)

Act I: Initiation:
(In eukaryotes):
1.Transcription factors recognize and bind to the promoter, "TATA" Box.
2.RNA polymerase II binds to the transcription factors and creates a Transcription Initiation Complex.
(In prokaryotes):
1. RNA polymerase II bind directly to the promoter region.
Act II: Elongation:
RNA polymerase untwists the double helix DNA, separates strands, then synthesises RNA as it base-pairs along the template in a 5'-> 3' direction.
The distinction between DNA and RNA synthesis? Instead of T pairing with A, it is U. And instead of new stand forming a bond with the template, it trails off from the polymeraseas RNA is single-stranded.
Act III: Termination:

(In eukaryotes):

RNA polymerase for hundreds of A nucleotides after the terminator, "AAUAA".
To protect the new RNA sequence from the hydrolytic enzymes in the cytoplasm, a G-cap is added to the 5' end, and a Poly A Tail, the collection of adenine nucleotides, at the 3' end.
But that's not all, RNA splicing is also needed to remove the introns (non-coding segments that also help in protecting the mRNA transcript) admist the exons, which actually codes for the amino acids(our next step with the mRNA). This splicing is accomplished by a spliceosome, with is formed by snRNPs (made up of protein and snRNA) and other proteins combining with the pre-mRNA. SnRNA base-pairs with the nucleotides at the end of the intron, and then the transcript is cut to release the intron, and the exons are spliced together.
(In prokaryotes):
Polymerase stops transcription at the end of the terminator, and the RNA and DNA are released.