ch 8 Flashcards
transcription starts at
promoter!!!!! BOTH
pro transcription occurs at
nucleiod/cytoplasm
transcription and translation is
coupled
promoter
sequence that recruits RNA pol for gene expression, contains -10 an d-35 sequences
-35 and -10 sequence
part of e coli promoter, consensus sequence
transcription start site number
+1
-10 sequence
Tata box or pribnow box
core enzyme
5 polypeptide chain, look like crab claw, catalyze polymerization
sigma factor
directs poly to promoter, helps with specific initiation of transcription
holoenzyme
core and sigma subunit, sigma can vary from each holoenzyme
different sigma subunits leads to
controlled transcription, will bind to different shit
sigma factor 70
important to life, housekeeping genes
key functions of sigma factor
- target RNA polymerase to holoenzyme and to specific promoters
- melt -10 region of promoter and stabilize it as ssDNA
- interact with other transcription factors
transcription steps
- initiation
- elongation
- termination
initiation steps
- promoter recognized and binded to
- close promoter complex formed
3.open promoter complex formed - abortive transcription
- promoter escape- sigma displaced?
close promoter complex formed
open up at -10, then starts-ish
elongation and sigma subunit relationship
no sigma required
transcription bubble
area of denatured DNA where rna synthesis is occurring- 20 nucleotides long
proofreading
rna poly has it but its not like ours
termination types
rho indie and rho dependent
rho indie relies on
inverted repeats to have hairpins, usually close to poly adenine (au) sequence
rho dependent
binds to rut, rho chases rna polymerase, no au sequence
constitutive genes
always on, housekeeping genes
repressible genes
on unless off
inducible genes
off unless on