Cytoskeleton-Centrioles By: Tim, Dylan, Jarrod, and Brianna

Internal Skeleton/Cytoskeleton Components of the Cytoskeleton Tubulin Protein Form Microtubules (to be discussed more later) Actin Filaments or actin proteins Form Microfilaments Intermediate Filaments The cytoskeleton of the cell is the overall structure of a eukaryote Contains filaments and motor proteins that allow components of the cell to move while still remaining rigid Allow cell movement from the cilia due to the moving of the filaments Cytoplasm Fluid in a cell (cytosol) Fills space not taken by organelles Breaks down some large molecules with dissolved enzymes

Intermediate filaments Provide mechanical support for the plasma membrane where it comes into contact with other cells or the extracellular matrix. Unlike microfilaments and microtubules, intermediate filaments do not participate in cell motility. Intermediate filaments are found in nearly all eukaryotic cells from multicellular organisms In epidermal cells and the axons and neurons, intermediate filaments are at least 10 times more abundant than microfilaments and microtubules. Reinforce cells and to organize cells into tissues.

Microfilaments (Actin filaments) Main Functions: Cytokinesis Changes in cellular shape Endocytosis Exocytosis Cellular contractions Microfilaments are thin strands of the protein actin. They transport myosin proteins whose movement helps pinch the cell from one into two. These filaments are flexible, yet still strong in order to support the cell.

Centrioles Centrioles are cylindrical arrays of 9 microfilaments, which are used for motion in the cell Constructed during the S phase of the cell cycle while DNA is being replicated Two centrioles come together to form a part of a centrosome

Centrosomes Centrosomes consist of 2 centrioles and are duplicated during the s phase of the cell cycle. During mitosis the centrosomes move to opposite sides of the cell. Spindle fibers, which are groups of microtubules, pull apart the chromosomes during anaphase, allowing the cell to duplicate.

References http://bscb.org/learning-resources/softcell-e-learning/cytoskeleton-the-movers- and-shapers-in-the-cell/ http://www.ncbi.nlm.nih.gov/books/NBK21560/ http://jcs.biologists.org/content/128/11/2009 http://www.biology-pages.info/C/Centrioles.html http://www.biology-pages.info/C/Cytoskeleton.html#microtubules