Term
| There are three types of filament in the cytoskeleton, name them... |
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Definition
| intermediate filaments, microtubules, and actin filaments. |
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Term
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Definition
| Give the cell mechanical strength and help reduce shear stress. Are intermediate in size and non polar |
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Term
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Definition
| Aide in the positioning of organelles, and intercellular transport. Are larger in size, and are polar. |
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Term
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Definition
| Help in shaping the cell, and total cell locomotion. Are smallest in size and are polar. |
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Term
| Filaments are made of small _______ ____, which are held together by ______. The _______ _____ help with organization |
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Definition
| protein sub units, a lot of weak non-covalent interactions, accessory proteins. |
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Term
| Filaments are made of Protofilaments, explain why these give the filaments strength. |
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Definition
| They can be multiple long strings of filaments, arranged end to end laterally, as well as end to end. Then, they twist around each other, making them strong |
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Term
| stability dependent subunits |
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Definition
| Actin- small globular, intermediate have longer subunits which makes them a little stronger. |
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Term
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Definition
| means the sides are different. Microtubles and actin are polar. |
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Term
The filaments of Microtublues
-forms
-these link together to form |
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Definition
Alpha and Beta Tubulins
form dimers.
protofilaments |
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Term
____ protofilaments interact to form a hollow tube.
Both alpha and Beta Tubulin bind ____ |
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Definition
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Term
| Where do you find microtubules? |
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Definition
| flagella and cilia; also find them in spindle complex; all cells have microtubles that originate in microtubule organizing centers (MTOC)aka centrosomes. |
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Term
| Beta tubulin is always on top- |
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Definition
| Positive end, it sticks out to periphery |
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Term
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Definition
| Immunofluorescence microscopy |
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Term
| drug that inhibits formation of microtubule filaments |
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Definition
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Term
Actin subunit is a ______ monomer called _______
g-actin binds ____
Organized - polar
2 protofilaments align _____ to one another and _____ together |
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Definition
globular, g-actin, ATP
parallel, twist |
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Term
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Definition
| More so for movement from cell to cell, the railroads of the cell. |
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Term
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Definition
| actin for cells that move themselves, more on the outside of cells. |
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Term
| Actin - ropelike structures that provide ______ as well as _______; important for ...; highly _____ structures |
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Definition
-Strength, Flexibility
-motility and structure
-dynamic |
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Term
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Definition
| is the formation of a motile cell surface that contains a meshwork of newly polymerized actin filaments. |
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Term
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Definition
| the phenomenon in which somatic cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment |
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Term
Intermediate Filaments
Are they polar or non polar?
Are they required in all cell types?
Shape? |
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Definition
| Non Polar, no, Coiled coil proteins |
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Term
Intermediate Filaments
2 _____ are parallel to each other in _____
2 dimers link together _____ - making a _____
_____ is considered the ____ - notice both ends look same |
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Definition
Monomers, dimers.
Anti-paralell, tetramer
Tetramer, protofilament |
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Term
Intermediate Filaments
Need_ parallel _____ to pack together (8x4=32) to make filament |
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Definition
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Term
| The 8 tetramers are twisted into a... |
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Definition
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Term
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Definition
| Nuclear Lamins, A, B, and C. Keratin, and Axonal neurons. |
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Term
| Epidermolysis bullosa simplex - |
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Definition
| a problem with the keratins (The boy whose skin fell off). |
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Term
More Keratin diseases
One nucleotide change - - |
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Definition
changes a leucine to a proline
disrupts the secondary structure (alpha helix) - disrupts the function of Keratin |
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Term
Amyotrophic lateral sclerosis (ALS or Lou Gehrig’s Disease) -
Linked to SOD mutations - how it causes defects in neurofilaments still not known |
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Definition
| accumulation and abnormal assembly of neurofilaments in motor neuron cell bodies |
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Term
Dynamic nature of Polar filaments
Polarity affects... |
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Definition
Filaments are always being made and broken down (polymerized and depolymerized)
... the rate of growth
+ end is faster at both adding and removing subunits
- end is the other end |
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Term
Three stages of filament growth:
Nucleation
Polymerization -
Maintain length -
Breakdown |
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Definition
- how do filaments start in the first place
-growth
treadmilling
catastrophe |
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Term
| 3 growth stages of filaments |
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Definition
Nucleation (lag)
Elongation (growth)
Steady State (equilibrium) |
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Term
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Definition
| The concentration of free subunits when the rate of addition is equal to the rate of dissociation |
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Term
If the number of subunits available is above the Cc...
If the number of subunits available is below the Cc...
There are different Cc for the.... |
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Definition
...you will be making filaments
...filaments will be depolymerizing
... + and - end of filaments |
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Term
Treadmilling...
Hydrolysis of _____occurs continuously
Occurs slowly on monomers ... |
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Definition
maintaining length.
ATP and GTP
not incorporated into filaments |
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Term
Treadmilling...
But, hydrolysis occurs rapidly once monomers are bound - ...
T-form (____) and D-form (_____) |
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Definition
...the ADP or GDP remain bound until removed
(ATP or GTP)
(ADP or GDP) |
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Term
Free subunits are ____
Rate of _____ affects whether the end is ______(_______) |
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Definition
T-form
addition
ATP or GTP (ATP cap or GTP cap) |
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Term
Cytosol is high in ATP and GTP
D-form leans toward ____
T-form _____
Addition at _____ and removal at ____ |
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Definition
disassembly while
toward assembly
+ end, - end |
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Term
Soluble subunits are in ___ form
Polymers are a mixture of...
Polymerization followed by ____ _____ |
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Definition
T
...T form and D Form.
Nucleotide Hydrolysis. |
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Term
Minus end addition is slow...
Plus end addition is fast...
Cc(T) is less than |
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Definition
hydrolysis catches up.
hydrolysis lags behind.
Cc(D) |
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Term
Drugs used to study filament formation
Drug actions |
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Definition
bind to monomers and prevent their addition to growing filaments - causes depolymerization
bind to filaments and stabilize their structures |
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Term
Actin Specific Drugs
Phalloidin - |
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Definition
| binds to actin filaments and stabilizes them (from mushrooms) |
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Term
Actin Specific Drugs
Latrunculin |
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Definition
| - binds subunits and prevents polymerization (from sea sponge) |
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Term
Actin-specific Drugs
Cytochalasin D |
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Definition
| - inhibits addition of monomers at the + end causing |
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Term
| Destabilization of actin causes cells to |
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Definition
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Term
Microtubule specific drugs
Taxol - |
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Definition
| widely used in cancer patients; binds and stabilizes microtubules (Yew tree bark); kills rapidly dividing cells (toxic) |
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Term
Microtubule specific drugs
Nocadazole |
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Definition
| - binds subunits and prevents polymerization |
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Term
Microtubules specific drugs
Colchicine - |
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Definition
| binds free tubulin leading to microtubule depolymerization (meadow saffron or autumn crocus) |
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Term
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Definition
| - dismantles neurofilament bundles in peripheral nerve axons and hence a neurotoxin |
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