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18: Cytoskeleton

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    Learning objectives

    1. Describe the traits and functions of the various cytoskeletal elements (microtubules, microfilaments, and intermediate filaments).
    2. Elucidate the general mechanism by which molecular motors move along cytoskeletal elements.
    3. Identify the molecular motors (dyneins, kinesins, and myosins) that partner with various cytoskeletal elements.
    4. Describe microtubule organizing centers, and their structures and functions.
    5. Explain the dynamic properties of cytoskeletal elements and how this relates to their construction and functioning.
    6. Elucidate the structure and function of cilia and flagella, and their differences and similarities.
    7. Elucidate the existence and importance of nonmuscle motility.

    (a) Microtubules: Hollow cylindrical shape composed of many small spheres. Measures 25 nm tall. (b) Microfilaments: 2 strands of actin subunits, denoted by small spheres, twisted into a helix shape. Measures 7 nm tall. (c) Intermediate filaments: Fibrous subunit of keratins coiled together. Measures 8-12 nm tall.

    Figure 18.1: Summary of the three major types of structural filaments.

    If you were to remove all the organelles from a cell, would the plasma membrane and the cytoplasm be the only components left? No. Within the cytoplasm, there would still be ions and organic molecules, plus a network of protein fibers that help maintain the cellʼs shape, secure some organelles in specific positions, allow cytoplasm and vesicles to move within the cell, and enable cells within multicellular organisms to move. Collectively, scientists call this network of protein fibers the cytoskeleton.

    Thumbnail: Grey, Kindred, Chapter 18. 2021. CC BY 4.0. Adapted from Figure 4.22. CC BY 4.0. From OpenStax.​​​​​​

    This page titled 18: Cytoskeleton is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Renee J. LeClair (Virginia Tech Libraries' Open Education Initiative) .

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