Cellular and flagellar movement is carried out by all of the following except -
Ans. is 'a' i.e., Intermediate filamentCytoskeleton o All cells have a cytoskeleton that : ?Maintains the structure of a cellPermits cell to change it shapeHelps in movemento Cytoskeleton is primarily made up of1. Microtubules2. Intermediate filaments3. Microfilaments1. MicrotubulesMicrotubules helps in motility of sperm, movement of cilia, leukocyte migration & phagocytosis, and formation and movement of spindle in mitosis.o Microtubules also provide the tracks for transpo of vasicles, organelles and mitochondria from one pa of the cell to another.Defect in organization of microtubules can inhibit sperm motility (male sterility) and immobilization of cilia of respiratory system --> kaagener's syndrome or immotile cilia syndrome.Colchicin inhibits assembly of microtubules--> Prevent migration of leukocytes and phagocytosis-4 Used in acute gout.Vinca alkaloids (Vincristine & Vinblastin) inhibit assembly of microtubules, while paclitaxel enhances polymerization of microtubules that make them so stable that they can not move apa --> Both these drugs inhibit mitosis and cause cell death. These drugs are used as anticancer drugs.2. Micrafilaments (Thin filaments)o They are made up of actin.o Actin is the most abundant protein in mammalian cells.Function of actin is essential for leukocyte movement and phagocytosis.Cytochalasin 'B' prevents polymerization of microfilaments.3. Intermediate filamentso They form a flexible scaffolding for the cell and provide stuctural suppo to resist external pressure.o These are keratin filaments (in epithelial cells), neurofilaments (in neurons), desmin filaments (musclecells), Vimentin filaments (in connective tissue cells) and glial filaments (in astrocytes). o These filaments may accumulate in ceain type of cell injury e.g.,(a) Mallory body or alcoholic hyaline is eosinophilic intracytoplasmic inclusion in liver is made up of keratin. It is characteristic of alcohol liver disease.(b) Neurofilaments (neurofibrillary tangle) are found in brain in Alzheimer's disease.
Intermediate filaments
Actin
Tubulin
Myosin