Cytoskeleton

Question 1

what does the cytoskeleton do

Answer 1

helps maintain shape, organization, polarity

Question 2

Protein filaments

Answer 2

all 3 function collectively for strength, shape, movement

Question 3

3 prtoein filaments

Answer 3

actin, intermediate, microtubules

Question 4

Structures of cytoskeleton

Answer 4

microvilli, desmosomes, adherence junction, apical + basolateral membranes

Question 5

Microvilli

Answer 5

increase surface area

Question 6

Desmosomes

Answer 6

cellular junctions, maintain mechanical integrity

Question 7

Adherens junction

Answer 7

complexes at cell to cell junctions

Question 8

Apical

Answer 8

towards lumen

Question 9

Basolatera

Answer 9

away from lumen

Question 10

what do protein filaments form

Answer 10

polarized + highly dynamic structures, depending on conditions

Question 11

Cytoskeleton enables

Answer 11

organization, shape/structure, resist deformation, stabilization, changes for movement

Question 12

Actin

Answer 12

determine shape, necessary for locomaotion, small, built for subunits, globular

Question 13

Microtubules

Answer 13

determines position of membrane-enclosed organelles, intracellular transport, large, built from subunits, globular

Question 14

Intermediate

Answer 14

provides mechanical strength, medium, built of small subunits, elongated + fibrous

Question 15

what is actin essential for

Answer 15

mechanical support, movement, shape/structure

Question 16

F-actin structure

Answer 16

helix of g-actin, 2 parallel protofilaments, flexible + thinner

Question 17

Polymerization

Answer 17

addition of monoers to either end

Question 18

Phases of polymerization

Answer 18

1. nucleation
2. elongation
3. steady state

Question 19

profilin

Answer 19

inhibits nucleation

Question 20

cofilin

Answer 20

promotes depolymerization

Question 21

ATP Binding + hydrolyses

Answer 21

monomers carrier ATP, ATP-actin, ADP-actin

Question 22

ATP-actin

Answer 22

higher binding, filament stability

Question 23

ADP-actin

Answer 23

easily dissociated, less stable

Question 24

Polymerization + Depolymerization

Answer 24

allows cells migration and interaction with environment, poly adds, depoly removes

Question 25

Actin binding proteins

Answer 25

determine shape and properties, fascin + filamin

Question 26

Fascin

Answer 26

linear bundles, add rigidity

Question 27

filamin

Answer 27

gel-like network

Question 28

Cell movement parts

Answer 28

stress fibers, filopodium

Question 29

stress fibers

Answer 29

contractile sturctures, anti-parallel

Question 30

Filopodium

Answer 30

finger-like extension, fibers are linear

Question 31

3 processes of movement

Answer 31

1. protrusion out front or on leading edge 2. stick to surface 3. drag rest by traction

Question 32

Examples of cell movement cells

Answer 32

ameoba, WBC, fibroblasts

Question 33

Cytokines

Answer 33

1 -> 2, contractile ring

Question 34

Motor proteins

Answer 34

all ATPases, associated with cytoskeleton

Question 35

Myosin family

Answer 35

myosin 1 (1 head/tail), Myosin 2 (2 heads, coiled tail), myosin V (mass transporters)

Question 36

Tropomyosin

Answer 36

binds with actin with 3 tropoins

Question 37

Troponin C

Answer 37

binds Ca and allows contraction

Question 38

Muscle contraction

Answer 38

releases CA, nervous system signal, triggers actin potential

Question 39

Phalloidin

Answer 39

staining actin filaments

Question 40

Alpha-amanitin

Answer 40

death cap toxin of muschroom

Question 41

Alpha-Tubulin

Answer 41

part of structure, cannot be hydrolyzed

Question 42

beta-tubulin

Answer 42

polymerized, grows/shrinks, ne be hydrolyzed

Question 43

Microtubules are composed of

Answer 43

alpha/beta heterodiers, stacked head+tails, folding into tube

Question 44

Dynamic instability

Answer 44

switches between growth + shrinkage, depend on GTP-binding domain

Question 45

Clinical relevance of dynamic instability

Answer 45

cancer therapy, neurodegenerative disease, cell migration + metastasis, development biology, infection + pathofen response

Question 46

MTOC

Answer 46

microtubule organizing center, centrosome is major

Question 47

Centrosome

Answer 47

2 cylinder called centrioles

Question 48

Centrioles

Answer 48

cylindrical organelle, spindle fiber development

Question 49

Cell division

Answer 49

MT rearrange to form bipolar mitotic spindle, astral microtubule-organized duplicated genetic material

Question 50

MAPs

Answer 50

microtubules-associated proteins, move vesiciles with pigments,

Question 51

Dynein

Answer 51

towards negative end, composed of two chains that make heads

Question 52

Kinesin

Answer 52

towards positive end, similar to dynein

Question 53

Structural roles of MAPs

Answer 53

Cilia + flagella, motility structures, dynein motor proteins that generate force for movement

Question 54

Paclitoxel (taxol)

Answer 54

binds + stabilizes microtubules, cytostatic drug, anticancer, interfere w/ spindle formation

Question 55

Colchicine/colcemid

Answer 55

binds substrates, prevents polymerization

Question 56

Vinblastine, vincristine

Answer 56

binds substrates, prevents polymerization

Question 57

Vinca alkaloids

Answer 57

binds irreversibilt to MT, interferons with mitotic spindle

Question 58

Intermediate Filaments

Answer 58

no polarity, associated with cell-cell junctions, strengthens + mechanical stability

Question 59

Intermediate Filaments composition

Answer 59

2 intertwined proteins bound by hydrophobic interactions

Question 60

Epithelial keratin

Answer 60

most diverse, anchors via desmosomes/hemidesmosomes, diagnosis's epithelial cancers

Question 61

Other filaments

Answer 61

neurofilaments, lamin, desmin

Question 62

Neurofilaments

Answer 62

along axon, provide strength + stability

Question 63

Lamin

Answer 63

mechanical stable

Question 64

Desmin

Answer 64

sacaffold function