5 The Cytoskeleton Free Online FlashCards

What is the cytoskeleton?

The cytoskeleton is a dynamic network of protein filaments that helps cells maintain shape, organize their interiors, and move.

What are microfilaments made of?

Microfilaments, also called actin filaments, are thin, flexible fibers made of actin subunits.

Where are actin filaments abundant, and what do they help support?

Actin filaments are abundant just beneath the plasma membrane, where they form part of the cell cortex and help support cell shape.

How can actin help a migrating cell extend its leading edge?

Growing actin filaments at the front of a migrating cell can push the membrane outward, forming a protrusion.

What force-generating role do actin and myosin perform together?

Actin interacts with myosin to generate contractile force, including during muscle contraction and the final separation of a dividing cell.

What distinguishes intermediate filaments’ protein building blocks?

Intermediate filaments are rope-like fibers made from different proteins in different cell types; examples include keratins and vimentin.

What mechanical role do intermediate filaments serve?

Intermediate filaments reinforce cells and help tissues resist pulling and stretching. They are generally less dynamic than actin filaments and microtubules.

What supports the inner surface of the nuclear envelope?

The nuclear lamina is a specialized intermediate-filament network that supports the inner surface of the nuclear envelope.

What are microtubules made of, and what is their shape?

Microtubules are hollow tubes built from dimers of α- and β-tubulin.

How do microtubules change dynamically?

Microtubules are polar, with two different ends, and can grow or shrink as tubulin subunits are added or removed.

How do microtubules help organize and transport materials inside cells?

Microtubules help position organelles and provide tracks for moving cargo through the cell.

What microtubule arrangement is characteristic of many motile cilia and flagella?

In many motile cilia and flagella, microtubules form a characteristic 9 + 2 arrangement. Their interactions generate bending.