Which structure is formed from polymerized G-actin?

The structure formed from polymerized G-actin is F-actin. G-actin, which stands for globular actin, is the monomeric form of actin. When these G-actin molecules polymerize, they assemble into long, filamentous structures known as F-actin, or filamentous actin. This filamentous actin is crucial for various cellular functions, including muscle contraction, cell motility, and maintaining cell shape.

F-actin forms part of the cytoskeleton and interacts with other proteins that facilitate dynamic cellular processes. This essential role highlights the importance of F-actin as a structural and functional component in eukaryotic cells.

In contrast, microtubules are made from polymerized tubulin, not actin, and intermediate filaments are composed of various proteins such as keratins and vimentin. Cilia are composed of microtubules organized in a specific arrangement for movement and are therefore unrelated to actin polymerization.