Topic 13 Flashcards

1
Q

3 types of protein filaments

A

actin, intermediate and microtubules

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2
Q

predominant cytoskeletal protein of cells

A

actin

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3
Q

filamentous actin

A

thin, flexible and consists of head to tail arrangement of g actin polymerized into filaments (helical structure)

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4
Q

actin polymerization is…

A

reversible

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5
Q

actin filaments are also known as…

A

microfilaments

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6
Q

globular actin

A

actin monomer that has tight binding sites

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7
Q

pointed (-) end of actin filament

A

slow monomer addition

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8
Q

barbed (+) end of actin filament

A

rapid monomer addition

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9
Q

ATP actin

A

associates with filaments more readily

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10
Q

ADP actin

A

dissociates from filaments more readily

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11
Q

treadmilling

A

equilibrium between rate of addition and removal of monomers; occurs in vitro

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12
Q

actin

stabilization, polymerization, depolymerization are all regulated by….

A

several actin binding proteins

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13
Q

formin

A

catalyze initiation of actin filaments

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14
Q

rate limiting step on initiation

A

initial polymerization of three actin monomers

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15
Q

profilin

A

stimulates exchange of ADP for ATP; associated with formin

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16
Q

When branching, formin and Arp 2/3 complex add actin monomers to which end of the chain?

A

barbed (+)

17
Q

actin networks

A

actin filaments cross-linked that form 3D meshwork’s with properties of semisolid gels

18
Q

actin bundles

A

actin filaments are cross-linked into closely packed arrays

19
Q

alpha actinin

A

in contractile bundles

20
Q

fimbrin

A

in non-contractile bundles

21
Q

actin bundling proteins

A

alpha actinic and fimbrin

22
Q

actin network forming proteins

A

have two flexible arms that interact with separate actin filaments to form a mesh structure

23
Q

cortical cytoskeleton

A

spectrin and actin

24
Q

Association of the ______________ with the plasma membrane proteins determines cell shape.

A

RBC cortical cytoskeleton

25
Q

stress fibres

A

bundles of contractile actin filaments; allows cells to exert force

26
Q

________________ play an important role in formation of cell projections and cell motility

A

actin microfilaments

27
Q

molecular motor

A

a protein that converts chemical energy in the form of ATP to mechanical energy, thus generating force and movement

28
Q

vimentin

A

forms a network extending out from nucleus to cell periphery

29
Q

desmin

A

connects contractile elements in muscle cells