Which cellular structure is formed by chains of actin?

Microfilaments, which are formed by chains of actin proteins, play a crucial role in various cellular processes. These structures are part of the cytoskeleton, providing shape and mechanical support to the cell. Actin microfilaments are involved in muscle contraction, cell motility, and the maintenance of cell shape. They can also participate in the formation of cellular extensions, such as lamellipodia and filopodia, which are important for cell movement and interaction with the environment.

While microtubules are composed of tubulin and intermediate filaments are made of various proteins that contribute to structural support, they are distinct from microfilaments. Pseudopodia, although they utilize actin for movement and structure, are formed as extensions of the cell membrane rather than being a defined cellular structure like microfilaments. The designation of microfilaments specifically to chains of actin emphasizes their unique role and composition in cellular architecture.