Describe how DNA is used to build proteins including: Transcription, post-transcript of mRNA (introns and exons), translation, and post-translation of proteins.

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Transcription is the process of creating a complimentary strand of RNA copy from a corresponding DNA sequence.  Both RNA and DNA are nucleic acids which are base pairs of nucleotides in a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes.  During transcription, a DNA sequence is read by an RNA polymerase which produces a complimentary antiparallel RNA strand.  As opposed to DNA replication, transcription results in an RNA complement that includes uracil (U) in all instances where thymine (T) would have occured in a DNA complement.  Transcription progresses like this:

1. DNA unwinds/unzips, as the hydrogen bonds break.

2. The free nucleotides of RNA pair with complementary DNA bases.

3. RNA sugar-phosphate backbone forms.

4. Hydorogen bonds of the untwisted RNA + DNA ladder break, freeing up new RNA.

5. If the cell has a nucleus, the RNA is further processed and then moves through the small nuclear pores into the cytoplasm of the cell.