What is the cytoskeleton?

The cytoskeleton is a complex and dynamic network of protein filaments and tubules found within the cytoplasm of many living cells. It plays a crucial role in maintaining the cell's shape, providing mechanical support, and facilitating cellular movement. Proteins such as microfilaments, intermediate filaments, and microtubules comprise the cytoskeleton, each contributing to the structural integrity and function of the cell.

This network is essential for various cellular processes, including cell division, intracellular transport, and the overall organization of cellular components. It allows cells to maintain their shape and resist deformation, while also playing a role in signaling pathways and regulating cell behavior.

The other options describe different cellular components. The rigid outer layer that provides structural support refers to the cell wall in plant cells, not the cytoskeleton. An organelle responsible for energy production is typically a mitochondrion, which converts nutrients into usable energy. The mention of internal membranes involved in protein synthesis relates to the endoplasmic reticulum and the Golgi apparatus, neither of which is directly associated with the cytoskeleton's functions.