Test Four Cytoskeleton Flashcards
1
Q
What is a cytoskeleton
A
Network of protein filaments throughout cytoplasm
2
Q
Cytoskeleton supports
A
The movement of organelles and vesicles
3
Q
What are the types of protein filaments
A
Intermediate filaments, microtubules, actin filaments
4
Q
Subunit of intermediate filaments
A
Fibrous proteins
5
Q
Function of intermediate filaments
A
Provide cellular strength when stretched
6
Q
Location of intermediate filaments
A
From nucleus to plasma membrane and connected by desmosomes
7
Q
Example of intermediate filament
A
Nuclear lamina
8
Q
What is nuclear lamina
A
Intermediate filament around nucleus to provide strength to nuclear strength
9
Q
Structure of intermediate filament
A
Strong and rope like elongated fibrous proteins
10
Q
Diameter of intermediate filaments
A
10 no
11
Q
Monomer of intermediate filaments
A
Strands have globular head and tail with a helix in the middle
12
Q
Dimer of intermediate filament
A
Coiled coils
13
Q
Tetramer of intermediate filament
A
Two coiled coils bound by noncovalent forces
14
Q
Location of intermediate filaments
A
Muscle cells, epithelial cell, along nerve axons for reinforcement and for protection
15
Q
What are the four classes of intermediate filaments
A
Keratin, vimentin and vimentin-related filaments, neurofilaments, and nuclear lamina
16
Q
Where are keratin filaments found
A
Epithelial cells
17
Q
Where are vimentin filaments found
A
CT, muscles and neuroglia cells
18
Q
Where are neurofilaments found
A
Neurons
19
Q
Nuclear lamina filaments are found where
A
All cells
20
Q
Example of keratin
A
Hair, nails, skin, claws, hooves, feathers, lining of gut
21
Q
Location of keratin
A
Stretch through cell to desmosome
22
Q
What are the accessory proteins that stabilize intermediate filaments
A
Plectin
23
Q
Function of plectin
A
Links intermediate filaments to microtubules and then to desmosomes
24
Q
What are some problems with intermediate filaments
A
Epidermolysis bullosa simplex
25
Example of mutations in plectin
Bullosa simplex, muscularis dystrophy, and neurodegeneration
26
Nuclear lamins disassemble when
Mitosis occurs
27
Nuclear lamins are phosphorylated by
Kinases
28
Example of problems with lamins
Progeria
29
What is progeria
Prevents cells from dividing, causes children to look old
30
Subunit of microtubules
Tubulin
31
Function of microtubules
Organizing chromosomes, moving organelles, involved with motor proteins, infrastructure of cell
32
Microtubules grow out of
Centrosome
33
Microtubules are a dimer of
Alpha and beta tubulin
34
What are protofilaments
Long strand of dimer microtubules
35
Microfilaments contain
13 protofilaments together in a hollow tube
36
Microfilaments have specific
Polarity, beta end with positive and alpha end with negative
37
What side of dimer microfilament adds to elongate
Positive end (beta)
38
What bond is between alpha and beta part of microtubule
Covalent bond
39
What bond is used to put a lot of microtubules together
Non covalent
40
Centrosomes are located where
Near nucleus
41
Centrosome is made of
Gamma tubulin in a ring that forms sphere
42
What in centrosome grows microtubules
MTOC’s
43
Function of MTOCs
Control number, orientation and location of microtubules
44
Centrioles are found
Inside centrosomes
45
Function of centrioles
Unknown
46
Centrioles made up of
Cylinder of short microtubules
47
Microtubules are in constant
Dynamic instability (changing)
48
What is needed to attach dimer of microtubules
GTP
49
GDP is microtubules causes
Shrinkage of tubules
50
Dimers of microtubules with GTP or GDP pack more tightly
GTP
51
What does GTP cap do in microtubules
When microtubule dimers are added too quickly for GTP hydrolysis and will keep growing
52
What causes disassembly of microtubules
GTP hydrolysis into GDP
53
What drug causes no microtubule assembly by binding to tubulin in cytoplasm
Colchicine
54
What drug causes microtubules to never disassemble by binding to microtubules
Taxol
55
What are the two cancer drugs that affect microtubule growth and disassembly
Taxol and colchicine
56
What protein that is associated with another cell structure and cause microtubule to stop assembling
Capping protein
57
Specialized microtubule cells have less
Dynamic instability
58
Specialized microtubule differentiated cells are usually
Polarized
59
Salvatore movement is normally
Directional and steady
60
Motor proteins bind to
Actin filaments or microtubules
61
How do motor proteins travel
By ATP hydrolysis
62
Motor proteins bind to other cells components such as
Vesicle or organelle to move them
63
What are the two families of motor proteins
Kinesins and Dyneins
64
Kinesins move
Away from centrosome
65
Dyneins move
Toward centrosome
66
Motor proteins contain
Globular ATP binding heads and cargo binding tails
67
What of motor protein walks along microtubules
ATP hydrolyzing head
68
What pulls and stretches ER membrane along microtubules
Kinesins
69
What pull golgi toward the centrosome along microtubules
Dyneins
70
Microtubules move what organelles
Golgi and ER
71
Cilia are
Hair like structures
72
What moves cilia
Dynein
73
What anchors cilia
Basal body
74
Cilia have what in their core
Microtubules covered by plasma membrane
75
Movement of cilia
Power stroke then recovery stroke
76
Function of cilia
Propel a cell through fluid, move fluid over cell surface, collecting food, moving mucus, moving eggs
77
Structure of flagella compare to cilia
Longer
78
Function of flagella
Motility
79
Structure of cilia and flagella
9 doublet microtubules in a ring around two microtubules
80
Movement of cilia and flagella
Core bends with help of accessory proteins
81
What motor protein helps cilia and flagella walk
Ciliary dyneins
82
Subunit of actin filaments
Actin
83
Function of actin filaments
Affects movement of cell surface, phagocytosis, cell division, crawling, muscle contraction
84
Location of actin filaments
Under plasma membrane
85
Structure of actin filaments
Short, globular actin molecules in a chain with polarity , thin and flexible
86
Actin monomers add or subtract from what end
Either
87
What is bound to actin monomers
ATP
88
What promotes disassembly in actin filaments
ATP hydrolysis
89
What drug prevents actin formation by binding to loose actin
Cytochalasins
90
What drug prevents actin disassembly by binding to actin filament
Jasplakinolides
91
What prevents actin monomers from polymerizing out of control
Thymosin and profilin
92
What other proteins control actin activity
Actin-bundling proteins, cross linking, filament severing proteins (gelsolin)
93
Example of actin
RBC
94
Cell cortex of actin filaments
Concentrated network of actin filaments linked by actin-binding proteins
95
The cell cortex of actin filaments provides what function
Mechanical strength and structural support
96
How do actin filaments in cells crawl
Protrusion from front grabs cytoplasm, adhesion from protrusion anchors and rest of cell drags forward
97
What is the protrusion caused by actin polymerization
Lamellipodia
98
What in actin is the stabilizing cell, anchor
Integrins
99
What are the exploration protrusions of actin filaments
Filapodia
100
What helps to form branched actin
Actin related proteins (ARPs)
101
How do ARPs work
Assembly at front and disassembly at back
102
What protein interacts with actin filaments to create movement of cell or muscle contraction
Myosin
103
What are myosin
Actin dependent motor proteins
104
Myosin 1 is for
Cellular movement
105
Myosin 2 is for
Muscle movement
106
How does myosin 1 work
One Globular head interacts with ATP and tail determines and grabs cargo
107
What in actin filaments help actin cytoskeleton movement
Receptor proteins
108
What protein changes organization of actin
Rho
109
What Rho protein in actin causes filopodia formation
Cdc42
110
What Rho protein in actin causes lamellipodia formation
Rac
111
Do all types of muscle use actin and myosin
Yes
112
Describe myosin 2
2 ATPase head and tail (coiled coil)
113
What on myosin creates the filament
Tails
114
What is a muscle fiber
Numerous cells fused into one long cell
115
Myofibrils mainly consist of
Sarcomere
116
What is the contractile element of muscle cell
Myofibrils
117
What makes up a sarcomere
Action and myosin 2 with Z disc
118
What is the regulator of tropomyosin
Troponin
119
What is rigor Mortis
No more ATP being produced, muscle is in constant contraction and stiffens
120
What are the energy requirements for skeletal muscle
ATP for myosin head, ATP for Ca2+ pump into the SR, ATP for Na/K pump to resort resting membrane potential in cell
121
Sources of energy in skeletal muscle
ATP stores, phosphocreatine, glycogen stores and oxidative phosphorylation
122
ATP stores last for
1 to 2 seconds
123
Phosphocreatine source of energy lasts for
5 to 8 seconds
124
Glycogen stores for energy last for
One minute
125
Oxidative phosphorylation for source of energy lasts
Indefinitely
126
The greater the number of cross bridges form the stronger
The generated force
127
What is isometric contraction
Increase in tension, no decrease in length of sarcomere
128
What is isotonic contraction
Decrease length of sarcomere and constant tension generated
129
What is eccentric concentration
Muscle is lengthening and joint is extending
130
What is concentration contraction
Muscle is shortening and joint is flexing
131
Describe fast twitch
Larger fibers, lower blood supply, fewer mitochondria, and extensive ER
132
Describe slow twitch
Smaller fibers, greater blood supply, many mitochondria, and myoglobin
133
What is a motor unit
One motor neuron and all of the muscle cells innervated by it
134
What is motor unit summation
Recruitment of motor units determines amount of force generated by muscle
135
What causes muscle to sustain its contraction
Rapid stimulation by motor neurons
136
Sustained contraction is called
Tetanus
137
What is treppe
Muscle will be weaker than a warmed up muscle k
138
Hypertrophy of muscle includes
Increase in number of myofibrils (diameter) and increase in number of sarcomere (length)
139
Atrophy includes
Denervation atrophy and disuse atrophy (loss of use)
