Outcome: Cytoskeleton

Demonstrate familiarity with various components of the cytoskeleton, including monomeric units.

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 shape of the cell, secure some organelles in specific positions, allow cytoplasm and vesicles to move within the cell, and enable cells within multicellular organisms to move. Collectively, this network of protein fibers is known as the cytoskeleton. There are three types of fibers within the cytoskeleton: microfilaments, intermediate filaments, and microtubules (Figure 1). In this outcome, we will examine each.

Microfilaments line the inside of the plasma membrane, whereas microfilaments radiate out from the center of the cell. Intermediate filaments form a network throughout the cell that holds organelles in place.

Figure 1. Microfilaments thicken the cortex around the inner edge of a cell; like rubber bands, they resist tension. Microtubules are found in the interior of the cell where they maintain cell shape by resisting compressive forces. Intermediate filaments are found throughout the cell and hold organelles in place.

What You’ll Learn to Do

  • Describe the structure and function of microfilaments.
  • Describe the structure and function of intermediate filaments.
  • Describe the structure and function of microtubules.

Learning Activities

The learning activities for this section include the following:

  • Reading: Microfilaments
  • Reading: Intermediate Filaments
  • Reading: Microtubules
  • Self Check: Cytoskeleton