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TRANSCRIPTION
Describe initiation.
TRANSCRIPTION
• RNA polymerase
– Prokaryotes
– Eukaryotes (pol I-III)
• Transcription unit
• Direction of elongation
Stages: Initiation
Stages: Elongation
Stages: Elongation
What are the 2 events that occur simultaneously in this picture?
In what organism can this happen? Prokaryote or eukaryote?
Stages: Termination
Prokaryotes:
◦ end of
termination
signal
Eukaryotes:
◦ past the
signal
AAUAAA
Which is a prokaryotic cell? Eukaryotic cell?
Spot the differences.
What occurs during RNA processing?
RNA Processing
RNA Splicing
Split genes
Aside from removing introns, what else happens during processing?
Both ends of pre-mRNA are usually
altered
Interior sections cut out
Splicing of remaining parts
*In eukaryotes
5’ end (5’ cap)
3’ end (Poly (A) tail)
Functions:
Protects mRNA from degradation
Ribosome binding
Facilitate export of mRNA from nucleus
• Small nuclear ribonucleoproteins (snRNPs)
– Recognize splice sites
• Spliceosome
– Cuts & pastes at splice sites
What are the 2 components of snRNPs?