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21 fall: Biochem > Test 2: Lecture 42 and 43 > Flashcards

Test 2: Lecture 42 and 43 Flashcards

1
Q

movements of the cell

A

Actin cytoskeleton and motors

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2
Q

movements inside the cell

A

Microtubule cytoskeleton and motors

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3
Q

structural support

A

Intermediate filaments

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4
Q

three types of cytoskeletal fibers

A

actin filaments
microtubules
intermediate filaments

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5
Q

actin filaments

A

Form stress fibers and cortical network of thin filaments in most cell types

Are the major component of muscle fibers

Mediate all types of motile and contractile behavior of cells

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6
Q

microtubules

A
  • A highly dynamic radial network of fibers
  • Mediate intracellular transport (vesicles move on microtubules)
  • Coordinate global cellular events, such as polarization and division
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7
Q

Intermediate filaments

A
  • A rigorous network of fibers that follows the microtubule cytoskeleton
  • Assist in cell shape maintenance and provide support for anchoring intracellular structures
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8
Q

___ coordinate global cellular events, such as polarization and division

A

microtubules

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9
Q

___ mediate all types of motile and contractile behavior of cells

A

actin filaments

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10
Q

___ assist in cell shape maintenance and provide support for anchoring intracellular structures

A

intermediate filaments

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11
Q

sizes of cytoskeletal fibers

A

actin: 7 nm

intermediate filaments: 10 nm (keratin)

microtubules: 20 nm (hollow tubes)

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12
Q

Actin has both generalized and ___ cellular roles

A

specialized

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13
Q

some roles of actin

A

Cell structure

Cytokinesis

Adhesion - keep epithelial cells toegther

Contractility - how cells divide

Cell motility - (fibroblast- actin moves/ walks cell)

Local organelle transport- act like railroad similar to microtubules

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14
Q

3 type of structures formed by actin in non muscle cells

A

stress fibers

cell cortex

filopodium

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15
Q

cell cortex of a fibroblast has ___

A

actin in random criss crossed directions

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16
Q

filopodium in fibroblast have actin in ___

A

tight parallel bundles

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17
Q

stress fibers in fibroblast have actin in ___

A

antiparallel contractile bundles

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18
Q

how does actin move cell

A

leading edge (lamellipodium)- actin polymerization extends plasma membrane

Myosin II contracts the back

little feet contain integrins

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19
Q

___ form muscle tissues in the
body (including striated
skeletal muscle,___ muscle, and
cardiac muscle)

A

myocytes

smooth

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20
Q

____ respond to nerve stimuli to produce mechanical force by contraction.

A

myocytes

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21
Q

what is special about cardiac muscle

A

striated

contract spontaneously by internal pacemaker

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22
Q

myocytes are the driving force for body movement and normal functioning of many organs, including ___, ___, and digestive system

A

heart

blood vessels

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23
Q

actin filaments

A

minus (pointed end/slow growing)

plus end (barbed end/ fast growing)

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24
Q

actin filaments interact with different actin-binding proteins to perform different functions such as ___

A
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25
Q

actin attaches ___, errors in this leads to ___

A

the cell membrane and into the extracellular matrix

metastasis of cancer cells (not held on tightly and break off and travel outside of tumor and infect other areas)

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26
Q

cells can change direction quickly by

A

breaking down and reforming actin in a new part of the cell

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27
Q

Dynamic changes in cellular actin allow cells to respond quickly to their environment, for example, during ___.

A

chemotaxis

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28
Q

Defects in cell adhesion and signaling can lead to ____

A

polycystic kidney disease

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29
Q

defects in actin structure can lead to ___

A

heart failure

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30
Q

Actin-based motility in bacterial ___

A

pathogenesis

bacteria get comet tails that can use actin filaments inside cell to move around cell quickly

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31
Q

three formations of myosin

A

muscle cells: bunch of myosin wrapped around each other with heads on outside, tails in center

non muscle: myosin tails attached to vesicle and walk down actin carrying vesicle

small muscle formation, 4 instead of a bunch

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32
Q

myosin is a ___

A

mechanochemical ATPases

used phosphorylation of ATP to ADP to create movement

Power stroke

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33
Q

what is a power stroke

A

how myosin walks down actin

Myosin converts ATP energy to produce power strokes along actin filaments

ATP attached to myosin

phosphorylated into ADP

causes movement of myosin (walks down actin)

34
Q

Actin form ___ in non-muscle cells and ___ in muscle cells

A

cortex and stress fibers

myofibrils

35
Q

actin mediate ___ and ___ by interacting with myosin motors

A

cell movement

muscle contraction

36
Q

___ mediate cell adhesion

A

actin

37
Q

actin mediate specialized types of local ___

A

organelle movement

38
Q

actin form ___ during division in animal cells to separate two daughter cells

A

contractile ring

39
Q

Microtubules mediate ___ transport

A

intracellular

rail road inside cells

in interphase cells- non dividing cells

40
Q

4 common arrays of microtubules

A
41
Q

in interphase cells microtubules grow from the ___

A

centrosome in a radial form

42
Q

ciliated cells microtubule formation

A
43
Q

dividing cells microtubule array

A
44
Q

microtubules are made of __

A

alpha and beta tubulin

hollow cylinders

polar, dynamic polymers

plus and minus end

20-25 nm constant width but variable length

plus end will gain length, while minus end will lose length

45
Q

most minus ends of microtubules are anchored at the ___, will add subunits to the ___ end toward the ___ of the cell

A

centrosome (near center of cell)

plus

outside

46
Q

minus end of microtubules are in the center of the cell? true or false

A

true

minus end anchored at centrosome in center of cell

plus ends at outer part of cell, grow outward

47
Q

true or false. plus end of microtubules are in the center of a cell

A

false, negative end in the center, plus end on the outside

48
Q

microtubules grow from the __ end to the __ end

A

minus

plus

49
Q

Microtubules mediate ___ over large distances

A

fast organelle transport

50
Q

vesicle with bound ___ move from + to - end of microtubules

A

dynein

51
Q

vesicle with bound ___ move from - to + end of microtubules

A

kinesin

52
Q

During mitosis, microtubules reorganize to form ___ and segregate chromosomes into two daughter cells

A

mitotic spindle

53
Q

microtubule drugs that favor depolymerized state

A

colchicine

colcemid

vinblastine

vincristine

prevent microtubules from polymerizing and depolymerizing- stops dividing but also prevents movement of organelles, can be very toxic for cell

54
Q

microtubule drugs that favor polymerized state

A

taxol

prevent microtubules from depolymerizing stops dividing

but still allows movement of organelles, less toxic

55
Q

some drugs use to treat aggressive cancers

A

microtubule drugs

attach to depolymerized or polymerized state

both stop cell from dividing, but drug that is attached to depolymerized state prevents organelles from moving which can be very toxic for cell

56
Q

taxol

A

microtubule drug that favors polymerized state

57
Q

two types of motors for microtubules

A

dynein

kinesin

58
Q

dynein

A

motor for microtubule

always moved + to - (outside to inside of cell)

Drives organelle transport, microtubule array
formation and maintenance

  • Drives spindle movements during mitosis
  • Drives movement of cilia and flagella that can propel the movement of certain cell types
59
Q

kinesin

A

motor of microtubules

moves - to + (inside to outside of cell)

(some can go opposite during mitosis)

Drives organelle transport

• Drives spindle and chromosome movements during mitosis

60
Q

Kinesin and dynein have opposite ___ on microtubules

A

polarity

61
Q

Microtubule motors, like myosin, move by converting ATP energy into ___

A

mechanical force

62
Q

myosin

A

Motor on actin

Drives muscle contraction

Drives local organelle movement over short distances

Drives cell motility together with actin polymerization

63
Q

___ are specialized non-centrosomal microtubule array that are driven by dynein to propel the movement of certain cells

A

Cilia and flagella:

64
Q

how does dynein make cilia and flagella work

A

9 +2 formation of microtubules

dynein holds two microtubules together, during power stroke the microtubules are stuck together, bend instead of move,

the bending from side to side cause movement

65
Q

immotile cilia syndrome

A

primary ciliary dyskinesia

Caused by dynein mutation

Diagnosed in humans, dogs, pigs, and
cows.

Phenotype: all cilia are immotile

• Immotile sperm - male infertility

• Immotile cilia in the respiratory tract
– respiratory disorders

66
Q

dynein mutation

A

Immotile Cilia Syndrome

male infertility and respiratory disorders

(Primary Ciliary Dyskinesia)

67
Q

microtubules form ___ in interphase cells that support cell polarization and intracellular organelle transport

A

radial arrays

68
Q

microtubules reorganize in mitosis to ___ equally to two daughter cells

A

segregate chromosomes

69
Q

microtubules mediate ___ over long distances

A

rapid organelle transport

70
Q

microtubules support the movement of cilia and ___

A

flagella

71
Q

Microtubule motors ___ move along microtubules in opposite directions

A

kinesin and dynein

72
Q

two types of intermediate filaments

A

cytoplasmic

nuclear

73
Q

types of cytoplasmic intermediate filaments

A

keratin

vimentin and vimentin related

neurofilaments

74
Q

type of nuclear intermediate filaments

A

nuclear lamins

envelope around nucleus

75
Q

keratin is found in

A

epithelia

76
Q

vimentin and vimentin related intermediate filaments are found in ___

A

connective tissue, muscle cells and neuroglial cells

77
Q

nuclear lamins are intermediate filaments found in __

A

all animal cells

envelope around the nucleus

78
Q

intermediate filaments can form __ structure

A

flexible rope like structures

79
Q

Intermediate filaments support the structure of cells and tissues by

A

form sheets that stretch in between cells and keep them connected to each other

80
Q

Epidermolysis Bullosa Simplex

A

C ells that express mutant keratins rupture
in response to mechanical stress.

disorder of intermediate filaments

epidermis and dermis detach from each other

Diagnosed in both humans and dogs.

21 fall: Biochem (44 decks)

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