BY: MARC WERNER AND ASHLEY GRAYDON
CYTOSKELETON FUNCTIONS Keeps organelles in anchored locations Establishes and supports the shape of the cell Helps transport materials within the cell An arrangement of protein fibers found in all eukaryotic cells Separates the chromosomes in mitosis and meiosis
CYTOSKELETON FIBERS Microtubules: Organizes the cell and moves materials within the cell Actin Filaments: Accountable for cellular compression Intermediate Filaments: Stabilizes the framework of the cell
MICROTUBULES Built by the monomers of alpha and beta tubulin Found in both animal and plant cells Straight, hollow cylinder walls made up of 13 protofilaments Grow at the end of each polymerized dimer There are two types of microtubule motors: -Kinesins- move toward the positive end of the microtubule -Dyneins- move toward the negative end of the microtubule
ACTIN FILAMENTS Protein Actin monomers polymerize to form long thin fibers Smallest of the cytoskeletal filaments Provides mechanical strength to the cell Anchors the centrosomes at opposite poles of the cell during mitosis Links transmembrane proteins to cytoplasmic proteins (ex cell surface receptors) interact with myosin filaments in skeletal muscle fibers to provide the force of muscular contraction
INTERMEDIATE FILAMENTS Are cytoplasmic fibers Have several types of intermediate filament: -Keratins- found in the epithelial cells and also form hair and nails -Lamins- form a lattice that stabilizes the inner membrane of the nuclear envelope -Nuerofilaments- strengthen the long axons of neurons -Vimentins- provide mechanical strength to the muscle and other cells
DISEASES CAUSED BY DEFECTIVE CYTOSKELETONS Sickle Cell Aneamia- produces defective hemoglobin which alters the red blood cells into the shape of a sickle, the lattice locks into the shape of a sickle, which obstructs the microcirculation Duchenne Muscular Dystrophy- Mutation in the dystophin gene disrupts the ability of the proteins to hold on to the cytoskeletal elements to the surface of the membrane