Major Aspects of Transcription

Transcription is the reading of DNA to make a copy of mRNA. Since the mRNA is made by complimenting one side of the DNA it is actually the same as the opposite side of the DNA.
Transcription occurs in Eukaryote cells as a method of sending out (multiple) copies of the information on a gene without actually sending the original DNA from the nucleus to the chemically destabilizing environment of the cytoplasm.

1) Initiation starts when RNA polymerase binds to a promoter region of the gene to be transcribed causing the DNA to unwind and separate.

2) RNA polymerase moves past the promoter to the start sequence of the gene being transcribed.

3) A complimentary (opposite) strand of is synthesized from 5' to the 3' end. Only one strand of DNA is used as the template (recall the mRNA will look like the opposite side of DNA except Thymine is replaced with Uracil).

4) When a terminator sequence is reached by RNA polymerase transcription stops.
- mRNA separates from DNA
- RNA polymerase separates from RNA

5) mRNA is then processed as follows....
- 7-methyl guanosine is used as the 5' cap
- a 3' polytail ( approx. 250 adenines) is added to the 3' end

6) Introns (noncoding regions) are excised by splicesosomes and rejoin the exons (coding regions) EXONS///INTRONS

7) The mRNA transcript is then ready to exit the nucleus via the ER on its way to the Ribosomes.

Overview of Protein Synthesis

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