Brainscape's Knowledge GenomeTM

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


See full index

Life Science 3 > L8: Regulation of Prokaryotic Transcription > Flashcards

L8: Regulation of Prokaryotic Transcription Flashcards

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

Genes are often organized as _____

A

operons

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

Prokaryotic genes are _____–one promoter direct the synthesis of a mRNA that can encode more than one proteins

A

polycistronicc

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

Polycistronic

A

One promoter direct the synthesis of mRNA that can encode more than one proteins

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

Operon

A

An arrangement of genes in a contiguous linear array

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

An arrangement of genes in a contiguous linear array

A

Operon

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

In an _____ a continuous strand of mRNA carries the message for a related series of enzymes (polycristonic mRNA)

A

operon

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

Why are genes organized into operons?

A
  • genes encoding enzymes in a common pathway can all be induced simultaneously
    • known as “coordinate control”
    • one mRNA expresses multiple proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Coordinate control

A
  • type of control where genes encoding enzymes in a common pathway can all be induced simultaneously
  • one mRNA expresses multiple proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  • type of control where genes encoding enzymes in a common pathway can all be induced simultaneously
  • one mRNA expresses multiple proteins
A

coordinate control

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

Transcription of the structural genes is controlled by _____ protein

A

repressor

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

_____ sequence determines first level of regulation

A

Promoter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Promoter sequence determines first level of regulation

A
  • weak promoters have poor consensus sequences and initiate transcription infrequently
  • strong promoters generally have good consensus sequences and initiate transcription often
  • many promoters are regulated by addition regulatory proteins as well
    • repressors inhibit transcription initiations (Lac repressor)
    • activators increase transcription initiation (CAP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

_____ promoters have poor consensus sequences and initiate transcription infrequently

A

weak

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

_____ promoters generally have good consensus sequences and initiate transcription often

A

strong

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

weak promoters have _____ consensus sequence and initiate transcription _____

A

poor

infrequently

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

strong promoters generally have _____ consensus sequences and initiate transcription _____

A

good

often

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

Repressors

A
  • inhibit transcription initiation
  • block transcription initiation
  • ex: lac repressor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Activators

A
  • increase transcription initiation
  • speeds up transcription
  • ex: CAP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

_____ inhibit transcription initiation

A

repressors

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

_____ increase transcription initiation

A

activators

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

An example of repressor

A

Lac operon

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

An example of activator

A

CAP

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

3 levels of transcription

A
  1. basal level
  2. repressed
  3. activated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

_____ _____ proteins can facilitate these distal interactions

A

DNA bending

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

Repressors usually block transcription initiation by:

A
  • interfering with RNA polymerase binding

- preventing open complex formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Lac operon consist of _____ genes under the control of a single operator

A

3

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

3 genes of lac operon

A
  1. lacZ
    • encodes beta-galactosidase, an enzyme tha tcatalyzes the hydrolysis of lactose
  2. lacY
    • encodes the lactose permease, required for transport of lactose into the cell
  3. lacA
    • encodes a transacetylase enzyme that transfers an acetyl group from acetyl-CoA to Beta-galactosides
      • the cell can use lactose as an energy source by producing the enzyme beta-galactosidase to digest lactose into glucose and galactose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

lacZ

A
  • encodes beta- galactosidase

- an enzyme that catalyzes the hydrolysis of lactose

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

beta-galctosidase

A

enzyme that catalyses the hydrolysis of lactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

enzyme that catalyzes the hydrolysis of lactose

A

beta-galactosidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

lacY

A
  • encodes for lactose permease

- required for transport of lactose into the cell

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

lactose permease

A

required for transport of lactose into the cell

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

required for transport of lactose into the cell

A

lactose permase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

lacA

A
  • encodes a transacetylase enzyme

- transfers an acetyl group from acetyl-CoA to Beta-galactosides

35
Q

transacetylase enyme

A

transfers an acetyl group from acetyl-CoA to Beta-galactosides

36
Q

transfers an acetyl group from acetyl-CoA to Beta-galactosides

A

transacetylase enzyme

37
Q

encodes for Beta-galactosidase

A

lacZ

38
Q

encodes for lactose permease

A

lacY

39
Q

encodes for transavetylase enzyme

A

lacA

40
Q

Cell can use _____ as an energy source by producing the enzyme beta-galactosidase to digest lactose into glucose and galactose

A

lactose

41
Q

Cell can use lactose as an energy source by producing the enzyme beta-galactosidase to digest lactose into _____ and _____

A

glucose

galactose

42
Q

High levels of lactose result in _____-_____ production

A

Beta-Gal

43
Q

High levels of _____ result in Beta-Gal production

A

lactose

44
Q

Hydrolysis to galactose and glucose sugras = _____ in cell

A

energy

45
Q

Hydrolysis to _____ and _____ sugars = energy in cell

A

galactose

glucose

46
Q

substrate and inducer used in _____ _____ studies

A

Lac operon

47
Q

Inducer: IPTG

A

will induce the lac operon but is not metabolized, so its concentration stays constant during an experiment

48
Q

_____ will induce the lac operon but is not metabolized, so its concentration stays constant during an experiment

A

IPTG

49
Q

Substrate:
Bacterial colonies expressing B-galactosidase turn blue on agar plates containing __-___, which is a substrate for B-galactosidase but is not an inducer

A

X-gal

50
Q

X-gal

A

A substrate for B-galactosidase that makes bacterial colonies expressing B-galactosidase to turn blue on agar plates

51
Q

lacI

A
  • not part of the lac operon but codes for repressor

- has separate promoter and is transcribed independently of lacZ, lacY, and lacA

52
Q

_____ is not part of the lac operon but codes for repressor

A

lacI

53
Q

Mutations

A

changes in the normal DNA sequence

54
Q

_____ are changes in the normal DNA sequence

A

Mutations

55
Q

_____ cells have mutations in the normal DNA sequence found in cells isolated from the wild

A

Mutant

56
Q

“wild type” sequence

A

DNA sequence found in cells isolated from natural sources in the wild

57
Q

____ are DNA sequence found in cells isolated from natural sources in the wild

A

“wild type” sequence

58
Q

Inducible synthesis

A

synthesis that is turned on by an inducer

59
Q

______ _______ is a synthesis that is turned on by an inducer

A

inducible synthesis

60
Q

Constitutive synthesis

A
  • synthesis at a constant level in the presence or absence of inducer
    • loses all regulatory control of the lac operon
61
Q

_____ _____ is a synthesis at a constant level in the presence or absence of inducer

A

Constitutive synthesis

62
Q

I- mutants

A

mutant in I gene, resulting in a defective repressor

63
Q

O^c mutants

A

mutant in the binding site (operator) for the repressor

64
Q

Mutant in I gene, resulting in a defective repressor

A

I- mutants

65
Q

Mutant in the binding site (operator) for the repressor

A

O^c mutants

66
Q

I- and O^c mutants can be distinguished by analyzing _____ _____

A

partial diploids

67
Q

I- and O^c mutants can be distinguished by analyzing partial diploids

A
  • both result in constitutive expression of B-galactosidase
  • since bacteria are haploid, a plasmid can be used to introduce a second copy of the lac operon into the cell
  • I- and O^c mutations behave differently in the cis vs. trans arrangement
68
Q

O^c mutation is physically linked to the _____ gene (cis)

A

Lac Z

69
Q

_____ _____ is the protein product of the I gene

- it is diffusible within the cell (trans)

A

Lac I Repressor

70
Q

Widetype situation

A

lac operon is transcribed only in the presence of an inducer

71
Q

Mutation in the lac repressor gene (lacI) results in _____ _____ because no repressor is made

A

constitutive expression

72
Q

Mutation in the operator results in _____ _____ because the operator site is lost and repressor can’t bind

A

constitutive expression

73
Q

When the repressor is supplied in trans, _____ is observed again

A

regulation

74
Q

When operator is supplied in trans, there is _____ ______

A

no effect

75
Q

lac operon is also under _____ control

A

positive

76
Q

Glucose metabolism is favored over _____ meabolism

A

lactose

77
Q

Level of glucose in media is detected by _____

A

cAMP

78
Q

high glucose = low cAMP = no CAP (low transcription)

A

low glucose = high cAMP = bring in CAP (high transcription)

79
Q

_____ binds to specific DNA sequences

A

CAP-cAMP

80
Q

Binding results in a bend in the _____

A

DNA

81
Q

_____ also interacts directly with the RNA polymerase to stimulate binding to weak promoter sequences

A

CAP-cAMP

82
Q

RNA polymerase binding at _____ _____ with the help of CAP

A

lac promoter

83
Q

CAP is recognized by the _____ of polymerase

A

CTD (carboxyl terminal domain)

84
Q

CAP is _____ which increases transcription

A

activator

Life Science 3 (9 decks)

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