chapter 5 Flashcards
replicon
region of the gene that contains the REPLICATION ORIGIN
sigma factor
in transcription of RNA, it recognizes and guides the RNA from -30 and -10 sites to the +1 site to begin transscribing (promotor region)
consensus sequence
each sigma factor knows which promotor to go to, to initiate transcription process
3 types of termination of RNA during the end of transcription
- intrinsic termintation - signals within the RNA transcript itself
- Rho (p) protein uses ATP to pull it apart
3.
wobble effect
happens in translation when you dont have enough anti codons (tRNA) for all the amino acids. so it just accepts the last anticode
ex: if it is supposed to be ATG then ATC will work just fine
this means you dont have to make so many tRNA’s and also decreases chances of heritable mutations
chaperons
they are protines that help other protiens fold. they supress incorrect folding.
a chaperon called the Trigger Factor (TF) accociates with the ribosome and succesfully helps fold many protiens.
about 25% of proteins need help folding
Translocation & Secretion (3types)
Translocation: moving proteins across plasma membrane
Secretion: out of cell into external environment (3 types)
Sec –> in all 3 domains and translocates Un-folded proteins across membrane
Tat –> only secretes folded protiens
YidC –> works with Sec
Two-step and One-step secreting Systems
one-step: directly from cytoplasm to extracellular
two-step: cytoplasm –> periplasm –> extracellular (V, II, IX)
inducers
makes repressor fall of operator
makes activator attatch to promoter
co-repressors
makes repressor attatch to operator
Inhibitor
makes activator attatch to promoter
riboswitches
attenuation
loops that form and either stop transcription or lets it continue.
Ex: trp operon.
continues in precnce of low trp
terminates it in precense of high trp
riboswitches
part of an mRNA transcript 5’ molecule that can bind and target small molecules
during transcription if the end-product is abundant then it will bind to the riboswitch and transcription will stop
during transcription if the end-product is needed, it will continue transcription
–> in translation it has to do with shine delagarno sequences (SD)
sRNA
less commonly used, sRNA regulates translation by trans-endoding and they can form stem-loop structures