Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

genetics > chapter 12 part 3 > Flashcards

chapter 12 part 3 Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

heat stress

A

45 degrees compared to 37 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what do E. coli use as a result of heat stress

A

alternative sigma factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what do alternative sigma factors do

A

activate expression of specialized heat stress response genes
- change promoter-recognition ability of the RNA polymerase core enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

heat shock genes

A

encode proteins that protect cells from certain types of heat-induced damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

at a high temperature, what sigma factor is unstable

A

70

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what alternative sigma factor is used in high temp

A

32

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what gene encodes sigma factor 32

A

rpoH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what does sigma factor 32 recognize

A

G-C rich sequences at the -10 position instead of the A-T rich Pribnow box

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the promoter for rpoH recognized by

A

sigma factor 70 when temperature is elevated or sigma factor 24

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does high temperature also change?

A

chaperone proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

chaperone proteins at normal temperature

A
  • bind to small amount of sigma factor 32 to inhibit it from forming holoenzyme RNA pol
  • targets it for degradation by proteasome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

chaperone proteins at high temperature

A
  • chaperones release sigma factor 32, leaving it free to join RNA pol
  • chaperones redirected to heat-damaged cellular proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

in bacteria, _________ regulation isn’t as common as __________ regulation

A

translational, transcriptional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

different types of translational regulation

A
  • translation repressor proteins
  • complementary antisense RNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

where to translation repressor proteins bind

A

mRNAs near Shine-Dalgarno sequence
- interfere with interaction between mRNA and 16s rRNA in small subunit to prevent translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what does complementary antisense RNA do

A

block mRNA translation
- creates doubled-stranded region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

ex. of antisense RNA regulation

A

IS10 regulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

2 promoters in the IS10 insertion sequence

A
  1. Pin
  2. Pout
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Pin

A

relatively weak, controls transcription of transposase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Pout

A

much stronger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

where is the Pout promoter embedded

A

transposes gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does the Pout promoter direct transcription of

A

antisense RNA complimentary to part of the transposase mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what happens when most of the transposase mRNA is bound to antisense RNA

A

very little transposase is made, transposition relatively rare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

riboswitches

A

when an mRNA binds a small regulatory molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

3 functions of riboswitches

A
  • regulates transcription
  • affects translation
  • alters mRNA stability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

a riboswitch regulates the transcription of which operon

A

thiamin (thi) operon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what does the thiamin operon code for

A

proteins of the biosynthetic pathway for thiamin pyrophosphate (TPP) production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

ex. of how riboswitch alters transcritpion

A

riboswitch mRNA in Bacillus subtilis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

low TPP concentration in Bacillus subtilis

A
  • TPP amounts too low for riboswitch binding
  • leads to antitermination stem-loop formation
  • transcription of operon genes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

high TPP concentration in Bacillus subtilis

A
  • TPP binds to riboswitch
  • generates termination stem-loop followed by poly-U sequence
  • prevents transcription
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

ex. of altering translation with riboswitches

A

riboswitch mRNA in E. coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what operon produces TPP in E. coli

A

thiMD operon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

low TPP concentration in E. coli

A
  • 5’ UTR of mrNA forms secondary structure that contains Shine-Dalgarno antisequestor stem-loop
  • Shine-Dalgarno sequence binds to 16s rRNA in small ribosomal subunit so start codon may initiate translation of operon mRNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

high TPP concentration in E. coli

A
  • TPP binds to riboswitch
  • forms mRNA stem-loop that prevents Shine-Dalagarno sequence and start codon from initiating translation
  • prevents translation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

ex. of riboswitch troll of mRNA stability

A

gene glmS in B. subtilus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what does glmS code for

A

glutamine:fructose-6-phosphate amidotransferase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is glutamine:fructose-6-phosphate amidotransferase involved in

A

production of sugar GlcN6P

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

when concentrations of GlcN6P are low

A

glmS is expressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

when concentrations of GlcN6P are high

A

GlcN6P binds to the riboswitch sequence in the glmS mrNA and induces mRNA cleavage and preventing translation

40
Q

for successful phage infection, genetic regulatory switches must be controlled by what?

A

phage gene expression to redirect action of host genes

41
Q

what phage is usually seen in phage infection

A

lambda phage

42
Q

lambda phage

A

temperate phage that can undergo the lytic or lysogenic cycle

43
Q

description of the lambda genome

A

composed of about 48 kb of linear double-stranded DNA, encoding nearly 60 genes

44
Q

what does the lambda genome do once inside the host cell

A

circularizes

45
Q

how does the lambda genome circularize

A

by joining of 2 single-stranded cohesive (cos) ends of about 12 nucleotides in length

46
Q

the lambda genome is organized as a series of ________

A

operons

47
Q

when does the expression of some operson begin in the lambda genome

A

immediately after circularization

48
Q

3 types of lambda genes

A
  1. immediate early genes
  2. delayed early genes
  3. late genes
49
Q

what lambda proteins are made first

A

N and cro

50
Q

the products of the immediate early genes compete for control of what?

A

genetic switch - can be either lytic or lysogenic

51
Q

where does transcription of the circularized lambda genome begin

A

2 promoters: PR, PL

52
Q

PR promoter

A
  • rightward transcription of early genes
  • lytic cycle
  • begins with Cro protein (repressor)
53
Q

PL promoter

A
  • leftward transcription of genes
  • lysogeny
  • transcribes N protein (antiterminator)
54
Q

how is N an antiterminator

A

blocks transcription termination by allowing expression of delayed early and late genes

55
Q

how does the regulation of lysogen begin

A

with protein N binding to 3 transcription terminating DNA sequences

56
Q

3 transcription terminating DNA sequences

A

tL, tR1, tR2

57
Q

tL unbound

A

blocks leftward transcription beyond N

58
Q

tR1 and tR2 unbound

A

prevent rightward transcription beyond cro and 3 other early genes

59
Q

what proteins are produced by leftward transcription

A

integrase and cIII protein

60
Q

what protein is produced by rightward transcription

A

cII

61
Q

how is cII stabilized

A

by binding to cIII

62
Q

what does the cII/cIII complex bind

A

promoter PRE to initiate leftward transcription of cI gene

63
Q

what is the cI protein also called

A

lambda repressor protein

64
Q

what does the cII/cIII complex also bind to

A

PL to produce additional integrase protein

65
Q

the genetic switch for lysis/lysogeny depends on a balance between what?

A

cro protein and lambda repressor (cI product)

66
Q

both cro and lambda repressor have an affinity for what?

A

operator sequences: OR1, OR2, OR3

67
Q

where are OR1, OR2, OR3

A

between PRM and PR

68
Q

entry into the lytic cycle requires transcription of what?

A

late genes, regulated by late promoters and late operators

69
Q

where are the late genes located

A

to the right of PR

70
Q

what do the three operator sequences contain

A

17-bp target sequence for binding of either cro or lambda repressor

71
Q

order of dimerized cro protein binding to operator

A

OR3, OR2, and OR1

72
Q

what happens when the pro protein is bound at the operator sequence

A

blocks access of RNA polymerase at PRM, preventing production of lambda repressor (cI)

73
Q

what does PRM stand for

A

promoter of repressor maintenance

74
Q

what does cro binding also stimulate

A

transcription from PR enhancing transcription of cro and other rightward genes

75
Q

Q gene

A

encodes Q protein - positive regulator of transcription of genes rightward of PR

76
Q

the late genes include those needed for what?

A

production of head/tail proteins and proteins needed for host cell lysis

77
Q

order of how dimerized lambda repressor protein binds to operator

A

OR1, OR2, and OR3

78
Q

how does the lambda repressor function on operator

A

as dimer and spans 17 bap of DNA at each operator sequence

79
Q

what does the lambda repressor protein bound at the operator sequences initiate

A

positive control at PRM - leads to continuous transcription of cI, maintains repression
- also activates integrase

80
Q

a large number of co-infecting phages favors what?

A

lysogeny
- prevents wiping out all the host cells in a population

81
Q

DNA damage to the host like UV radiation can trigger entry into what?

A

lytic cycle

82
Q

if the host cells are actively growing, what is favored

A

lytic - new phage can easily find new host

83
Q

if host cells are growing poorly, what is favored

A

lysogeny - waits until ideal conditions

84
Q

what is the competition between the cro and lambda repressor protein

A

for binding to the operator sites

85
Q

lysogeny is a ____-_________ state

A

semi-permanent

86
Q

how can lysogeny continue for an extended time

A

by ongoing binding of lambda repressor to operator

87
Q

induction

A

process that brings lysogeny to an end and reinitiates lytic cycle

88
Q

what is induction primarily triggered by

A

DNA damage

89
Q

what does DNA damage activate

A

DNA repair

90
Q

what protein is part of the DNA repair cascade and is used in induction

A

RecA

91
Q

what kind of activity does RecA also have

A

protease activity - activated by UV light damage to DNA

92
Q

what happens when bacterial DNA is damaged by UV light

A

protease activity of RecA is activated

93
Q

what does the protease activity of RecA target

A

lambda repressor monomers and cleaves off the C terminus

94
Q

what happens when RecA targets the lambda repressor monomers

A

operator sequences exposed - positive regulation of cI and negative regulation of cro end

95
Q

what happens when lambda repressor leaves the operator

A

cro protein binds to the exposed operators

96
Q

what happens when cro proteins bind to the exposed operators

A

expression of Xis

97
Q

what does Xis produce

A

enzyme excisionase - removes lysogen from its integrated location

genetics (47 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions