C ENTRAL D OGMA Fundamental principle of molecular genetics, which states that genetic information flows from DNA to RNA to proteins

The Genetic Language Uses 4 Letters Written Into 3-Letter Words

I NTRODUCTION During transcription the DNA code is chemically rewritten as an RNA code Transcription: divided into 3 sequential stages 1. Initiation 2. Elongation Termination

I NITIATION In prokaryotes and eukaryotes begins with RNA polymerase Binds to the DNA strand, unwinds the helix near the beginning of a gene The binding occurs at the promoter which is a nucleotide sequence that lies just before the gene A key to the promoter sequence in the eukaryotes is TATA box

TATA B OX A region of the DNA with high percentage of TA bases, which is recognized by the RNA polymerase Prokaryotes have a TATAAT sequence A and T because 2 hydrogen bonds, less energy needed to break RNA expends less energy The part of the gene that is transcribed into RNA is called the Transcription Unit

E LONGATION No primer needed 5’ to 3’ direction The opposite strand of DNA is known as the coding strand, it contains the same base pair sequence as the new RNA RNA elongates as nucleotides are added one at a time The new RNA molecule winds temporarily with template DNA into hydrid RNA/DNA double helix

E LONGATION C ONTINUED.. Beyond this region RNA unwinds from DNA When a cell requires a particular protein they need to produce thousands or even millions of copies example. A single red blood cell contains 375 million hemoglobin molecules

T ERMINATION Transcription is terminated when RNA polymerase recognizes the termination sequence In prokaryotes 1 termination mechanism involves a protein binding to the mRNA and stopping transcription or when mRNA binds with itself in a hairpin loop In eukaryotes 1 termination is string of A The newly made RNA descoiatates from the DNA template