Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
22 Cards in this Set
- Front
- Back
When does tryptophan repressor bind to and shut down the operon?
|
When there is high levels of tryptophan, it is opposite of catabolic, anabolic where product is formed
|
|
Leader sequence
|
-control region found on mRNA
-encodes short petide that as far as is know does nothing -secondary structue of the leader RNA, as well as last two tryptophan codons, are how it controls trp expression |
|
Attenuation (low tryptophan)
|
Low tryptophan = ribosome stalls at the 2 tryptophan codons, preventing formation of first hairpin.
- hairpin resulting is not a terminator, so transcription continues |
|
High tyrptophan
|
-allows ribosome to move quickly and fall off at stop codon
-allows terminator loop to form -the tryptophan-synthesizing genes are transcribed |
|
Lambda phage
|
-can either have a lytic life cycle or a lysogenic life cylce
-which one is controlled by the lambda repressor, C1 -repressor binds to operators and represses transcription -repression of lytic genes is controlled by antiterminators |
|
Lambda phage has a complex regulatory region
|
yes
|
|
N and Q act as what?
|
termination factors
|
|
Binding at Or1, Or2, and Or3 regulates what?
|
Pr and Prm
|
|
Genetic switch of phage lambda
|
Or1, Or2, Or3 binding turns off lytic genes
|
|
cL binding at Ol and Or regulates transcription from PL, Pr, and Prm
|
Yes
|
|
Activating lysis
|
-lysogenic phage can be activated to become lytic
-UV light activates the SOS response -C1 repressor cleaves itself and can't repress anymore -Expression of lytic genes -Lysis of bacterium |
|
RNA degradation
|
RNA must be eliminated quickly so that the bacterium can respond quickly to environmental changes
-halflife of RNA is about 2 minutes -RNA is degraded by the degradosome |
|
Ribosome is made primarily of what?
|
RNA
|
|
tRNAs carry amino acids to the ribosome and are the link between what two things?
|
RNA and protein
|
|
Both are transcribed from DNA and processed to their functional form
|
Yes
|
|
rRNA
|
-50% of RNA made by cell
-extremely strong promoters -promoters can be regulated |
|
rrn Operons contain both...?
|
rRNA and tRNA genes
|
|
What increases transcription of rrn operons?
|
UP element
-distal and proximal subunits binding to alpha CTD subunits of RNA polymerase |
|
rRNA and tRNA are more abundant in faster growing E. coli cells
|
-faster means more ribosomes per cell and DNA molecule
|
|
rRNA operons are subject to feedback regulation
|
Yes
|
|
rRNAs and tRNAs are subject to postranscriptional processing
|
-mature rRNA and tRNA are terminated by a 5' monophosphate
-mature " " are smaller than primary transcripts -all tRNA molecules contain bases other than A,C, G, and U that are not present in primary transcript |
|
RNase P
|
-made mostly of RNA
-active site is made of RNA, not protein |