Transcription - Jan 30 Flashcards
Transcription
synthesis of a single stranded RNA in the 5’ to 3’ direction
RNA polymerase
enzyme that catalyzes transcription
RNA polymerase can start transcription de novo
without a primer (unlike DNA polymerase)
RNA polymerase is powerful because
while transcribing, it can unwind DNA, elongate transcript, release finished transcript, and restore DNA double helix after finishing
Transcription begins and ends at
binding of RNA polymerase to promoter sequence, terminator sequence
General Transcription Factors are
(at least six proteins) required to recruit RNA polymerase to the promoter and initiate transcription
Mediator Complex
bridges transcriptional regulatory proteins to the promoter
Transcriptional Activator Proteins
bind to enhancers (which appear before promoters) and increase the rate of transcription
What are the 3 stages of transcription?
Initiation, Elongation, Termination
Terminator
causes RNA polymerase to dissociate from the template DNA, ending transcription
Transcription Factors include
general transcription factors, activators, and repressors
Exons
code for the protein and are spliced to create the actual mRNA
Introns
do not code for protein and must be removed for the mRNA to be properly translated
Polyadenylation
adds a poly(A) tail (AAAAA) to the 3’ end
5’ capping
needed to initiate translation of an mRNA