Ch 10

Question 1

external signals can include

Answer 1

temperature
pH
O2 levels
nutrients
solute concentrations

Question 2

external signals trigger _______

Answer 2

sensor proteins

Question 3

sensor proteins trigger

Answer 3

an internal signal

Question 4

an internal signal triggers

Answer 4

internal function

Question 5

internal function triggers

Answer 5

gene expression

Question 6

gene expression triggers

Answer 6

DNA promoter

Question 7

ways to control gene expression at the DNA level

Answer 7

-modify nucleotides (methylation)
-rearrange DNA sequences to alter expression
-phase variation

Question 8

control of gene expression at transcription level

Answer 8

affects RNA polymerase

Question 9

control gene expression via mRNA stability

Answer 9

mRNA has a half-life

Question 10

control gene expression at the translational level

Answer 10

affect ribosome function

Question 11

control gene expression at the post-translational level

Answer 11

affect protein function -> modify or degrade the protein

Question 12

when are constitutive genes expressed

Answer 12

always!

Question 13

regulatory proteins include

Answer 13

repressors and activators; perform repression/induction/corepressor/depression

Question 14

induction/de-repression

Answer 14

gene expression initiated (ON)

Question 15

repression/co-repressor

Answer 15

gene expression stopped (OFF)

Question 16

pt 2 begins here

Answer 16

yipeee

Question 17

tryptohan operon

Answer 17

genes of a biosynthetic pathway; for tryptophan synthesis

Question 18

tryptophan operon is regulated via ______

Answer 18

repressor (TrpR)
co-repressor (tryptophan)

Question 19

when tryptophan is low or not present:

Answer 19

derepression; transcription proceeds

Question 20

tryptophan acts as a corepressor by

Answer 20

binding aporepressor -> active holorepressor forms; blocks transcription of Trp operon

Question 21

transcriptional attenuation definition

Answer 21

secondary strategy for regulating tryptophan synthesis

Question 22

transcriptional attenuation uses the ribosome as

Answer 22

a sensor of amino acids levels via transcription translation of leader sequence prior to trpE called trpL

Question 23

2 adjacent tryptophan codons are embedded in

Answer 23

the transcript sequence

Question 24

translating the leader ->

Answer 24

intracellular levels of charged tryptophan

Question 25

a reduction in energy sources requires a slow down in

Answer 25

ribosome formation due to the reduced cellular growth rate

Question 26

the stringent response results in a

Answer 26

decrease in ribosomal RNA transcripts

Question 27

____ is a starvation induced response

Answer 27

stringent response

Question 28

RelA is an

Answer 28

enzyme? works to form ppGpp

Question 29

ppGpp interacts with

Answer 29

RNA polymerase, decreasing expression of different genes; including rRNA genes and tRNA genes

Question 30

phase variation is

Answer 30

alteration of protein-coding DNA sequences of bacterial cell surface proteins

Question 31

phase variation results in

Answer 31

immune avoidance; pathogens bypass host immune system

Question 32

salmonella enterica flagellar protein

Answer 32

in the host, can switch between flagellin proteins H2 (fljB) and H1 (flijC)