DNA Transcription

Initiation:
- Transcription machine is assembled
- Transcription Factors spot out the promoter (TATA box)  and termination (AAUAA) region on either strand and begin copying the base sequences to make pre-mRNA.
- For each gene only one strand of double strand DNA is transcribed
- The strand being used to make the pre-mRNA is called the template (antisense) strand and the other strand is the coding (sense) strand
- RNA polymerase II crates an initiation complex
- DNA unwinds and RNA polymerase II starts transcription

Elongation:
- The coding strand and the RNA strand are very similar with Thymine being replaced with Uracil
- Nucleotides are added to the 3' end (OH)
- The m-RNA strand stars from the promoter and copies until the AAUAA
- The pre-mRNA is anti-parallel with the template strand and transcribes downstream

Termination:
- Once the RNA polymerase reaches the AAUAA sequence, transcription stops
- Pre-mRNA cuts off and  the DNA strands get winded back together
- Pre-mRNA is then guarded by a G-Cap on the 5' side and Poly-A-Tail on the 3' side due to enzymes in the cytoplasm that try to break down the mRNA
-Pre-mRNA contains useless sequence parts called introns that are not needed. They are taken out of the mRNA by spliceosome and the eons are connected.