Chapter 14 Part B

Front 1

When does tryptophan repressor bind to and shut down the operon?

Back 1

When there is high levels of tryptophan, it is opposite of catabolic, anabolic where product is formed

Front 2

Leader sequence

Back 2

-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

Front 3

Attenuation (low tryptophan)

Back 3

Low tryptophan = ribosome stalls at the 2 tryptophan codons, preventing formation of first hairpin.
- hairpin resulting is not a terminator, so transcription continues

Front 4

High tyrptophan

Back 4

-allows ribosome to move quickly and fall off at stop codon
-allows terminator loop to form
-the tryptophan-synthesizing genes are transcribed

Front 5

Lambda phage

Back 5

-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

Front 6

Lambda phage has a complex regulatory region

Back 6

yes

Front 7

N and Q act as what?

Back 7

termination factors

Front 8

Binding at Or1, Or2, and Or3 regulates what?

Back 8

Pr and Prm

Front 9

Genetic switch of phage lambda

Back 9

Or1, Or2, Or3 binding turns off lytic genes

Front 10

cL binding at Ol and Or regulates transcription from PL, Pr, and Prm

Back 10

Yes

Front 11

Activating lysis

Back 11

-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

Front 12

RNA degradation

Back 12

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

Front 13

Ribosome is made primarily of what?

Back 13

RNA

Front 14

tRNAs carry amino acids to the ribosome and are the link between what two things?

Back 14

RNA and protein

Front 15

Both are transcribed from DNA and processed to their functional form

Back 15

Yes

Front 16

rRNA

Back 16

-50% of RNA made by cell
-extremely strong promoters
-promoters can be regulated

Front 17

rrn Operons contain both...?

Back 17

rRNA and tRNA genes

Front 18

What increases transcription of rrn operons?

Back 18

UP element
-distal and proximal subunits binding to alpha CTD subunits of RNA polymerase

Front 19

rRNA and tRNA are more abundant in faster growing E. coli cells

Back 19

-faster means more ribosomes per cell and DNA molecule

Front 20

rRNA operons are subject to feedback regulation

Back 20

Yes

Front 21

rRNAs and tRNAs are subject to postranscriptional processing

Back 21

-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

Front 22

RNase P

Back 22

-made mostly of RNA
-active site is made of RNA, not protein