5.8: The Cytoskeleton
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- Ying Liu
- City College of San Francisco
State 4 different functions associated with the cytoskeleton of eukaryotic cells.
The cytoskeleton is a network of microfilaments, intermediate filaments, and microtubules. The cytoskeleton functions to:
- give shape to cells lacking a cell wall;
- allow for cell movement,e.g. , the crawling movement of white blood cells and amoebas or the contraction of muscle cells;
- movement of organelles within the cell and endocytosis;
- cell division, i.e., the movement of chromosomes during mitosis and meiosis and the constriction of animal cells during cytokinesis.
We will now take a closer look at microtubules, microfilaments, intermediate filaments, centrioles, flagella, and cilia.
Microtubules
Microtubules are hollow tubes made of subunits of the protein tubulin. They provide structural support for the cell and play a role in cell division, cell movement, and movement of organelles within the cell. Microtubules are components of centrioles, cilia, and flagella (see below).
Microfilaments
Microfilaments are solid, rodlike structures composed of actin. They provide structural support, and play a roll in phagocytosis, cell and organelle movement, and cell division.
Intermediate filaments
Intermediate filaments are tough fibers made of polypeptides. They help to strengthen the cytoskeleton and stabilize cell shape.
Centrioles
Centrioles are located near the nucleus and appear as cylindrical structures consisting of a ring of nine evenly spaced bundles of three microtubules. Centrioles play a role in the formation of cilia and flagella. During animal cell division, the mitotic spindle forms between centrioles.
Summary
- The cytoskeleton is a network of microfilaments, intermediate filaments, and microtubules.
- The cytoskeleton has a variety functions including, giving shape to cells lacking a cell wall, allowing for cell movement, enabling movement of organelles within the cell, endocytosis, and cell division.