Cytoskeleton Flashcards

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1
Q

What is the cytoskeleton?

A

A network of filaments providing structural integrity to the cell

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2
Q

The cytoskeleton is used for…

A

…transportation within the cell

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3
Q

The cytoskeleton allows movement of …

A

… the cell and cellular projections

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4
Q

What is the cytoskeleton responsible for?

A

cellular polarity

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5
Q

The cytoskeleton is not always…

A

…permanent, can be rapidly remodelled even within permanent structures

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6
Q

Protofilaments are made up of …

A

…smaller subunits

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7
Q

protofilaments are built by…

A

…repetitive assembly of small soluble proteins

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8
Q

Protofilaments are weak…

A

…non-covalent interactions between monomers

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9
Q

Polymerisation and depolymerisation can be used to …

A

…do mechanical work

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10
Q

Distribution and behaviour regulated by …

A

…associated ‘accessory proteins’

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11
Q

Protofilaments are controlled by…

A

…extracellular and intracellular signals

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12
Q

Filaments are made of …

A

…protofilaments

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13
Q

Lateral bonds between protofilaments hold …

A

…filaments together

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14
Q

Arrangement depends on …

A

…the filament type

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15
Q

The eukaryotic cytoskeleton has …

A

…three major components

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16
Q

The eukaryotic cytoskeleton has three major components which are:

A

Microfilaments

Microtubules

Intermediate filaments

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17
Q

What colour are microfilaments?

A

Red

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18
Q

What colour are Microtubules?

A

Green

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19
Q

Narrowest type of microfilament?

A

7nm diameter

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20
Q

Microfilaments are …

A

…Actin monomers (G-actin), globular polypeptide

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21
Q

Microfilaments are polymers of…

A

…F-actin

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22
Q

Microfilaments are ATP/ADP…

A

…binding sites

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23
Q

How do microfilaments assemble?

A

Assemble head to tail, giving polarity

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24
Q

Two parallel protofilaments in a…

A

…right-handed helix

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25
Q

Microfilaments are crosslinked by …

A

…accessory proteins to form bundles, or networks

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26
Q

Polymerisation of microfilaments initiated by …

A

…actin related proteins (ARP)

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27
Q

Plus end of microfilaments gains more …

A

…monomers than it loses

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28
Q

Minus end of microfilaments loses …

A

…more monomers than it gains

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29
Q

Microfilaments have a […] structure, known as […]

A

Microfilaments have a DYNAMIC structure, known as TREADMILLING

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30
Q

ARPs found at …

A

…end of actin polymers, and can bind to side of other fibres, creating a web.

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31
Q

Examples of parallel bundles of microfilaments?

A

Microvilli
Muscle

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32
Q

Examples of mesh of microfilaments?

A

Lamellepodia

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33
Q

Actin-myosin interactions cause…

A

…contraction of the ring, resulting in separation of daughter cells.

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34
Q

Villi and Fibrin link …

A

…the actin fibres into tight bundles of 20-30 fibres

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35
Q

Myosin I connects…

A

… the actin to the plasma membrane

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36
Q

What is attached to the end of microfilaments?

A

A cap of proteins is attached to the end of microfilaments.

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37
Q

Actin microfilaments run…

A

…the entire length and support each microvillus

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38
Q

Cross linking actin-binding proteins link…

A

…microfilaments to eachother and to the plasma membrane

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39
Q

Pathogen is detected by …

A

…surface receptors.

40
Q

Signals are transmitted into…

A

…the cell to modify actin arrangement.

41
Q

Cell moves towards location of …

A

…strongest signal, up a concentration gradient (chemotaxis).

42
Q

What are microtubules made from?

A

Made from α-tubulin, β-tubulin heterodimer subunits

43
Q

Microtubules involve…

A

…GTP/GDP binding.

44
Q

HOw many protofilaments in microtubules?

A

13

45
Q

Different types of interactions in microtubules?

A

Longitudinal α-β interactions
Lateral α-α and β-β interactions

46
Q

Structure of microtubules?

A

Very stiff and straight

47
Q

What is required in microtubules to start polymerisation?

A

nucleation

48
Q

GTP bound dimers added to …

A

… + end

49
Q

GTP hydrolysed in …

A

…polymer

50
Q

GTP hydrolysis of terminal dimers causes a …

A

…change in shape of protofilaments -catastrophe

51
Q

Microtubules are insulated by…

A

…γ-tubulin at - end

52
Q

Wheres the microtubule-organising centre located on animal cells?

A

in centrosome in animal cells

53
Q

How do microtubules grow?

A

Grow outwards, from centre of cell

54
Q

Microtubules are used to do what?

A

Used to organise position of organelles

55
Q

Microtubules can determine…

A

…cellular polarity eg. Epithelial cells centrosome is near apical membrane

56
Q

Three types of microtubule involved in mitosis:

A

Aster microtubules
Polar microtubules
Kinetocore microtubules

57
Q

Whats the red layer in microtubules?

A

flagella

58
Q

Whats the blue layer in microtubules?

A

movement

59
Q

Function of intermediate filaments?

A
  • Mechanical stability
  • Provide mechanical resistance to external stresses, eg erythrocyte deformation
60
Q

The type of intermediate filament depends on…

A

…location

61
Q

Intermediate filaments are not found in all cell types or all animals, only in…

A

…‘squishy’ animals.

62
Q

Intermediate filaments details:

A
  • α helix, forms parallel dimer, then staggered antiparallel tetramer
  • Many disulphide bridges between cysteine molecules
  • No nucleoside binding
  • No polarity
  • Rope-like
  • Tough, form protective covering
63
Q

How many classes of intermediate filament proteins?

A

1) Keratin
2) Vimentin and vimentin-related
3) Neurofilaments
4) Nuclear lamins

64
Q

Function of keratins?

A

Organelle positioning, cell shape, and integrity

65
Q

Function of vimentin and vimentin related and neurofilaments?

A

Regulate axon diameter, and axon growth

66
Q

Function of nuclear lamins?

A

Structural function and transcription regulation

67
Q

Where are keratins found?

A

in epithelia

68
Q

Where are vimentin and vimentin related found?

A

in connective tissue, muscle cells, and neurological cells.

69
Q

Where are neurofilaments found?

A

in nerve cells.

70
Q

Where are nuclear lamins found?

A

in all animal cells.

71
Q

Keratin intermediate filaments strengthen …

A

… the epithelium

72
Q

Keratin attach to…

A

…desmosomes and hemidesmosomes

73
Q

α-Keratin based intermediate filaments form …

A

…protective coverings on mammals

74
Q

The cytoskeleton allows cells to …

A
  • move
  • divide
75
Q

The cytoskeleton maintains…

A

…cell shape and intracellular organisation

76
Q

Cytoskeleton provides…

A

…mechanical strength

77
Q

Cytoskeleton acts as a…

A

…intracellular road network, for transport within the cell

78
Q

Myosins- At least 18 types, almost all …

A

…move towards + end

79
Q

How many types of myosin?

A

18

80
Q

Myosin II involved in …

A

…muscle contraction

81
Q

Myosin V involved in…

A

…vesicle/organelle transport

82
Q

Myosin I anchors…

A

…actin bundles to membrane in microvilli

83
Q

How many families of kinesins?

A

at least 14 families

84
Q

kinesins move towards…

A

… + end

85
Q

Kinesins carry…

A

…membrane enclosed organelles or bind other microtubules

86
Q

Dyenins move towards…

A

… - end

87
Q

Dyenins are the…

A

…fastest

88
Q

Function of Cytoplasmic dyenin?

A

vesicle trafficking and golgi localisation

89
Q

Axonemal dyenins drive…

A

…movement of cilia and flegella

90
Q

ATP is hydrolysed to…

A

…ATP is hydrolysed to

91
Q

ADP disassociates from …

A

…head

92
Q

In the Prokaryotic cytoskeleton, homologues of all three components found in ….

A

…bacteria

93
Q

In the Prokaryotic cytoskeleton, FtsZ polymerises into…

A

…ring

94
Q

In the Prokaryotic cytoskeleton, MreB (and Mbl) serve as…

A

…scaffold for cell wall synthesis

95
Q

In the Prokaryotic cytoskeleton, there are no…

A

…molecular motors

96
Q

No molecular motors is thought to…

A

… limit cellular complexity and size

97
Q
A