17.2 Transcription
- RNA polymerase: put together RNA nucleotides to DNA strand
- In bacteria:
- Promoter- where RNA starts
- Terminator- ends
- Transcription unit- piece that is transcribed
- 3 stages of Transcription
- Initiation
- Elongation
- Termination
- Promoter called a TATA box is crucial in forming the initiation complex in eukaryotes
ELONGATION OF THE RNA STRAND
- As RNA Polymerase moves along the DNA, it untwists the double helix, 10-20 bases at a time
- Transcription progresses at a rate of 40 nucleotides per second in eukaryotes
- Gene can be transcribed simultaneously by several RNA polymerases
- Nucleotides are added to the 3' end of the frowing RNA molecule
TERMINATION OF TRANSCRIPTION
- In eukaryotes, RNA polymerase II transcribes the polyadenylation signal sequences
- The RNA transcript is poreleased 10-35 nucleotides past this polyadenylation sequence
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