Lecture 10: Cell's Cytoskeleton

Vocabulary flashcards covering the components, structures, dynamics, and motility functions of the cytoskeleton based on Lecture 10 notes.

Cytoskeleton

A network of fibers extending throughout the cytoplasm that organizes the cell's structures and activities, anchoring many organelles.

Microtubules

The thickest of the three components of the cytoskeleton, consisting of hollow rods about $25\,nm$ in diameter and about $200\,nm$ to $25\,microns$ long.

Microfilaments (Actin Filaments)

The thinnest components of the cytoskeleton, built as solid rods about $7\,nm$ in diameter made of a twisted double chain of actin subunits.

Intermediate Filaments

Cytoskeletal fibers with diameters in a middle range of $8\text{--}12\,nm$, composed mostly of proteins such as keratin, which act as permanent fixtures in the cell.

Tubulin Dimer

A protein dimer consisting of $\alpha\text{-tubulin}$ and $\beta\text{-tubulin}$ that polymerizes head-to-tail to form protofilaments using energy from GTP.

Catastrophes

Events in microtubule disassembly where GTP hydrolysis causes protofilaments to peel and curl, disassembling the microtubule structure.

Centrosome

A region near the nucleus in animal cells from which microtubules grow out, containing a pair of centrioles.

Centrioles

Structures in animal cells featuring nine triplets of microtubules arranged in a ring, functioning to organize the centrosome in which they are embedded.

9 + 2 Arrangement

The characteristic microtubule structural arrangement in cilia and flagella, consisting of a central pair of singlet microtubules surrounded by nine outer doublet microtubules.

Basal Body

A structure anchoring the cilium or flagellum, formed by the mother centriole attached to the inner plasma membrane, containing nine triplet microtubules.

Dynein

A motor protein whose arms alternately grip, push, release, and re-grip adjacent microtubule doublets to drive the bending movements of cilia and flagella.

Cortex

A 3-D network formed by microfilaments just inside the plasma membrane to help support the cell's shape.

Pseudopodia

Cellular extensions that extend to allow cells to crawl along a surface during localized actin- and myosin-driven amoeboid movement.

Cytoplasmic Streaming

A circular flow of cytoplasm within plant cells driven by actin-myosin interactions and sol-gel transformations that speeds the distribution of materials within the cell.