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Flashcards in 2.07 Cytoskeleton Deck (128)
0

Extensive intracellular network of filamentous structures extending throughout the cytoplasm

Cytoskeleton

1

Provides rigid physical support for certain parts of cells

Cytoskeleton

2

Physical support for certain parts of cells

Intracellular scaffolding

3

Function of cytoskeleton

Structural support
Cell motility
Cell regulation

4

Stabilize and balance opposing forces
Spherical/partially spherical shell structure of lattice shell based on a network of great circles on the surface of a sphere

Geodesic dome

5

Changes in cell location and limited movements of parts of the cell

Motility

6

Transmit mechanical signals that rearrange the nucleoli and other structures

Cell regulation

7

3 main types of cytoskeletal fibers

Microtubules
Microfilaments
Intermediate filaments

8

Types of cytoskeleton can be distinguished

Biochemically
By TEM

9

Contain alpha and beta tubulins
Grow or shrink as more tubulin molecules are needed or removed

Microtubules

10

Important for directing intracellular traffic
Motor molecules also carry vesicles or organelles to various destinations along monorails provided by cytoskeleton

Polarity

11

Function of microtubules

Mitosis spindle
Intracellular trafficking of vesicles
Cilia and flagella
Axoplasmic flow of materials along neuronal processes

12

Locomotory cells

Kinesins
Dyneins

13

Central structural supports in cilia and flagella

Microtubules

14

Move unicellular and small multicellular organisms by propelling water past the organism
Move fluid over a surface if anchored on large structures

Microtubules

15

Move more like oars with alternating power and recovery strokes

Cilia

16

Cilia generate force ______ to the axis of the cilia

Perpendicular

17

Undulatory movement

Flagella

18

Flagella
Eukaryotic

Undulating, wave-like, sinusoidal

19

Flagella
Prokaryotic

Rotatory

20

Only vertebrate cell that has flagella

Sperm

21

Both cilia and flagella have the same ________ arrangement

9+2 pattern

22

Bending of cilia and flagella is driven by the arms of a motor protein _____

Dynein

23

Drugs that inhibit microtubules
Anti - gout

Colchinine

24

Disrupts microtubules that facilitate the movement of WBC towards the site of inflammation to lessen inflammation

Colchicine

25

Drug that inhibit microtubules
Anti-fungal

Griseofulvin

26

Inhibit cellular division of fungus

Griseofulvin

27

Drug that inhibit microtubules
Chemotherapeutic agents
Stopping the mitosis of cancer cells

Vinbalstine
Paclitaxel

28

Rare generic disorder characterized by immobile cilia of the respiratory tract and the Fallopian tubes or sperm flagella

Kartagener Syndrome
Primary ciliary dyskinesia

29

Immobile cilia
Infertile
Dynein-deficient

Kartagener Syndrome
Primary ciliary dyskinesia

31

Forms microfilaments

Actin

32

Causes the bending of the cilia and flagella

Dynein

33

Monomeric globular

G-actin

34

At physiologic ionic strength and in the presence of magnesium, G-actin ____ noncovalently to form an insoluble double helical filament

Polymerizes

35

Has a pitch or repeating structure every 35.5 nm

F-actin

36

Function of microfilament

Resist tension
Form a 3D network

37

The shape of the microvilli in the intestinal cell are ____, anchored to a network of intermediate filaments

Supported by microfilaments

38

Thicker filaments composed of a motor protein, _____, interdigitate with the thinner actin fibers

Myosin

39

In other cells, less organized ____ cause localized contraction

Actin-myosin aggregates

40

Contracting belt of microfilaments divide the cytopalsm of animal cells during the cell division, also termed as ____

Cytokinesis

41

Localized contraction also drives ______, in which pseudopodia extend and contract through the reversible assembly and contraction of actin subunits into microfilaments

Amoeboid movement

42

Clathrin-mediated endocytosis, also referred to as _____, occurs at a membrane indentions where the triskeion-shaped protein clathrin accumulates

Receptor-mediated endocytosis

43

Filaments with an axial periodicity of 21 nm and a diameter of 8-10 nm that is intermediate between the other two

Intermediate filaments

44

More stable and permanent fixtures of the cytoskeleton than the other two classes

Intermediate filaments

45

Functions of intermediate filaments

Bearing tension
Reinforce cell shape and fix organelle location
Relatively stable components of the cytoskeleton
Rather deformable proteins that can be stretched severla times their initial length

46

Most types of IF are cytoplasmic, ____ are nuclear

Lamins

47

Cell-cell adhesion

Desmosomes

48

Cell-matrix adhesion

Hemidesmosomes

49

At the cell membrane, some keratins interact with ____ and ____ via adapter proteins

Desmosomes; hemidesmosomes

50

Distribution of IF
Lamins

Nuclear lamina

51

Distribution of IF
Keratins

Epithelial lining, hair, nail (Type I-acidic)

52

Distribution of IF
Desmin

Muscle

53

Distribution of IF
Vimentin

Various mesenchymal cells

54

Distribution of IF
Glial fibrillary acid protein

Glial cells

55

Distribution of IF
Peripherin

Neurons

56

Distribution of IF
Neurofilaments (Low, High, Medium)

Neurons

57

Two diseases due to abnormalities in IF

Hutchinson-Gilford Progeria
Epidermolysis Bullosa Simplex

58

Important for structural scaffolding of the nucleus

Lamin A

59

Mutations in the gene encoding ____ and ____ causes Hutchinson-Gilford Progeria

Lamin A and Lamin C

60

Hutchinson-Gilford Progeria
Appearance of ____

Accelerated aging

61

Mutations in genes encoding _____ causes epidermolysis bullosa simplex

Various keratins

62

In epidermolysis bullosa simple, there is a diminished capacity of various layers of the skin to resist mechanical stresses due to abnormalities in keratin structure as manifested by _____

Blistering

63

Hollow tubes, wall with 13 tubulin molecules

MIcrotubules

64

Fibrous proteins supercoiled into the thicker cables

Intermediate Filaments

65

2 intertwined strands of actin

Microfilaments

66

Maintain cell shape (tension bearing elements)
Changes in cell shape
Muscle contraction
Cytoplasmic streaming
Cell motility and division

Microfilament

67

Maintain cell shape (compresion-resisting girders)
Cell motility
Chromosome movement in cell division
Organelle movement

Microtubules

68

Maintain cell shape
Anchorage of nucleus and other organelles
Formation of nuclear lamina

Intermediate filaments

69

Most mammalian cells are located in tissues surrounded by a complex _____, which is a major component of connective tissue

ECM

70

ECM is a _____ component present within all tissues and organs

Noncellular

71

ECM initiates crucial biochemical and biomechanical required for tissue ____, ____ and ____

Morphogenesis, differentiation, homeostasis

72

Functions of ECM

Structural support
Compartmentalize tissues
Provide rigidity
Signaling
Highway for cell migration during development, in normal tissue maintenance, and in injury or disease

73

Composition of ECM

Water, protein, polysaccharide

74

3 major classes of biomolecules (ECM)

Structural proteins
Specialized proteins
Proteoglycans

75

Most abundant protein in animals

Collagen

76

Collagen has _____ structure containing three alpha-polypeptide chains arranged in right-handed supercoil

Triple helix

77

3 AA for collagen

Glycine, proline, hydroxyproline

78

Types of Collagen

Fibril-forming
Network-forming
Fibril-associated collagen with interrupted triple helices
Anchoring
Beaded-filament forming

79

Continuous, regular arrangement results in characteristic D period of 67nm

Fibril-forming collagen

80

Examples of fibril forming collagen

I, II, III, V, VI

81

Forms network in basement

Collagen IV
Network-forming collagen

82

Molecular sieving
Molecular filtration

Network-forming

83

Examples of network-forming collagen

Type IV, VII, X

84

Short collagens with interruptions
Linked to collagen II and carries a GAG chain

Fibril-associated collagens with interrupted triple helices

85

Found at the surface of fibril-forming collagen

Fibril-associated collagens with interrupted triple helices

86

Examples of FACITs

IX, XII, XIV

87

Provide functioning integrity by connecting epithelium to stroma

Anchoring collagen

88

Example of anchoring collagen

Type VII

89

Form structural links with cells
Type VI

Beaded-filament forming

90

Collagen type
Reticulin

Type III

91

Collagen type
Cartilage

Type II

92

Collagen type
Basement membrane

Type IV

93

Collagen type
Bone

Type I

94

Collagen synthesis
Undergoes _____ before becoming part of the extracellular collagen fiber

Posttranslational modification

95

Precursor of collagen

Preprocollagen

96

Cardinal principle in the biosynthesis of collagen

Self-assembly

97

Important cofactor in the hydroxylation of selected proline and lysine

Vitamin C

98

Once formed, collagen is metabolically stable. Breakdown of which is increased during _____ and ____.

Starvation
Inflammatory States

99

Excessive collagen deposition in the liver fibrosis due to prolonged injury to the tissue

Hepatic cirrhosis

100

Collagen defects
Collagen I

Osterogenesis imperfecta

101

Collagen defects
Collagen I and V

Ehlers Danlos syndrome

102

Collagen defects
Collagen IV

Alport Syndrome

103

Collagen defects
Collagen III

Certain arterial aneurysms

104

Collagen defects
Collagen VI

Ullrich muscular dystrophy

105

Reticulin fibers cannot hold integrity of your vascular structures

Certain arterial aneurysms

106

Collagen defects
Collagen IX and XI

Certain chondrodysplasias

107

Bone fragility, short stature, bone deformities, teeth abnormality, gray-blue sclera, hearing loss

Osteogenesis Imperfecta

108

Osteogenesis imperfecta is caused by mutatation in either type I collagen ______

COL1A1 or COL1A2

109

Liver spots on skin, spongy gums, bleeding from mucous membane, depresion, immobility

Scurvy

110

____ is required for prolyl hydroxylase and lysyl hydroxylase activities

Ascorbate

111

Elastin is important in ____ and _____ in tissues

Extensibility and elastic recoil in tissues

112

Exhibits a variety of random coil conformations that permit _____ and ____

Stretch and subsequent coil

113

Large glycoproteins whose primary structures are dominated by cbEGF domains that in the presence of calcium, adopt a rodlike structure

Fibrillin

114

Structural component of microfibril
Secreted ECM by fibroblasts and becomes incorporated into the insoluble microfibrils

Fibrillin-1

115

Provide a scaffold or deposition of elastin

Microfibril

116

Caused by dominant fibrillin-1 mutations
Skeletal, ocular, cardiovascular defects
Deficiency of elastin-associated microfibrils

Marfan syndrome

117

Syndrome that may result from alterations in cell signalling

Marfan syndrome

118

Hyperaerated lung
Damage to the lung air sacs that affects breathing

Emphysema

119

Increased alveolar size reduces the surface area for gas exchange

Emphysema

120

Elastic fiber biogenesis
Assembly of microfibrils >> association of tropoelastin aggregates with the microfibrils >> crosslinking of tropoelastins with each other by _____ to form polymers

Lysyl oxidase

121

Primary protein component of the basal lamina

Laminin, entactin, type IV collagen

122

Basement membranes are involved in a multitude of biological processes: __, ___, ___

Cell proliferation
Cell differentiation
Cell migration

123

Maintain cell polarization and organization as well as tissue structure

Basement membrane

124

Basement membrane acts as _____ in the kidney between vasculature and the urinary space

Filtration barrier

125

Laminins
3 elongated polypeptide chains (A, B, B2) linked together to form _____

Elongated cruciform shape

126

Binding site for type IV collagen, heparin, integrins on cell surface

Laminin

127

Assemble into trimers in the ER and are secreted as trimers intro extracellular space

Laminin Trimer Polymerase

128

Full-sized laminin trimers can ____ into a macromolecular network through a short-arm interactions

Self-polymerize