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42 Cards in this Set
- Front
- Back
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intermediate filaments
general description |
10nm
strong-gives cell tensile strength Not dynamic (lamins) |
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Microtubules
general description |
25nm diameter
tracks for motility (vesicles, segregation of chromosomes) framework for cilia |
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Actin microfilaments
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7nm diameter
very flexible-polymerization of actin tracks for motility-frequently associated with the plasma membrane changes in cell shape Dynamic |
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What is the subunit for microtubule assembly and what nucleotide is bound to it
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tubulin dimer +GTP
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in what tissue types are keratin filaments found?
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intermediate filament in epithelial cells
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which cytoskeletal element is most important for changes in cell shape
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actin microfilaments
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the filaments that provide strength to axons in the nervous system are called
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microtubules
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centrosomes act as organizing centers for most cellular organelles because they function as assembly sites for ____________
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microtubules
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kinesin motors move toward the ________ ends of microtubules
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plus end (beta side up)
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why is ciliary assembly essential for vision
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vision requires display of light receptor, rhodopsin, on sensory cilia in rod and cone cells
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Name the four different kinds of intermediate filaments
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keratins, vimentin, desmin and glial fibrillary acidic protein, neurofilaments, nuclear lamins
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what is a keratin
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type of IF found in epithelial cells. can co-assmble to form mixed filaments. provides strenght. essential for the body surface barrier function of skin
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what is vimentin
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type of IF widespread in cells of mesodermal origin
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what is desmin
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IF present in muscle cellswhere it holds together adjacent myfibrils
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What is GFA ( glial fibrillary acidic protein
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IF that is in astrocyctes and glial cells--supports CNS
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what are neurofilaments
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IF with three subunits co-assmble into filaments that extend along the length of axons, providing these long cellular extensions with tensile strength
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what are nuclear lamins
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IF present as a meshwork on the inner surface of the nuclear membrane of all cells. Phosphorylation assembles and reassembles it during the cell cycle
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Typing of what kind of tissue can be useful in the diagnosis of epithelial cancers?
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keratins
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epidermolysis bullosa is a skin blister disease caused by a mutation in ___________
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epidermal keratins
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Only (alpha/beta)________ tubulin can hydrolyze its bound GTP to GDP
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beta
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alpha and beta tubulin contain ____ binding sites
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GTP
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Formation of the tubulin dimer protects the GTP on ______(alpha/beta) tubulin
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alpha
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To assemble microtubules, three things are necessary:
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GTP
Mg++ critical subunit concetration |
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The fast growing end of the assembling microtubule is called the ____ end
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plus
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The plus ends of microtubules dissasemble when __________
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all GTP is hydrolyzed
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What helps to determine microtubule distribution by stabilizing minus ends
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Microtubule organizing centers of two centrioles making one centrosome contains gamma-tubulin which nucleate mictorubule assembly
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What is the difference between mature microtubules and immature mictotubules?
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mature ones are not dynamic
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Which microtubule motor conducts plus end directed motility
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kinesins
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which microtuble motor conducts MINUS end directed motility
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dyneins
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Give two examples of where microtubule motors are found
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nerve axons and ER
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Organelle distribution is maintained by
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microtubules
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What is an axoneme
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9+2 doublet microtubules plus associated dynein and other structures
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Axonemes make up which two structures
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cilia and flagella
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how does movement occur in cilia and flagella
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microtubule sliding through minus end directed dyneins
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Where are motile cilia present in the human body?
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brain, tetinal photoreceptro, respiratory, renal monocilia, sperm, fallopian tube
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where are nonmotile cilia present in the body
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mechanoreceptors in cartilage, kidney function, specialized sense organs like ear eye and nose
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colchicine
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anti-microtubule drug
used to treat gout disrupts formation of mitotic spindle |
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vinblastine/vincristine
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blocks mitotic spindle assembly
treat cancer anti-microtubule drug |
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taxol
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arrests mitosis by binding mitotic spindle
powerful anticancer drug anti-microtubule drug |
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kartagener's syndrome
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lack of motility in what should normally be motile cilia, leading to respirtory disease, infertility, and situs inversus
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polycystic kidney disease
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genetic disease involving protein encoding for assembly of primary (non-motile) cilia resulting in abnormal growth regulation of epithelial cells resulting in cysts
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diseases associated with disruption of sensory cilia
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mechel-gruber syndrome, alstrom syndrome, nephrophthesis, and bardet-biedl syndrome, kartagener's syndrom, polycistic kidney disease
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