Final answer:
The internal skeleton of a cell is called the cytoskeleton, a structure formed by interlinking protein filaments and tubules that provides support and assists in various cellular functions.
Step-by-step explanation:
The internal skeleton of a cell is composed of the cytoskeleton. The cytoskeleton is a complex network of interlinking filaments and tubules that spread throughout the cytoplasm, providing the necessary framework for the cell. This cellular "skeleton" is comprised of three main types of fibers: microtubules, microfilaments, also known as actin filaments, and intermediate filaments. It offers structural support, maintains cell shape, assists in cellular movements, and plays a crucial role in intracellular transport, cell division, and the positioning of organelles.
Actin filaments and microtubules are particularly dynamic, capable of rapid assembly or disassembly to adapt to the cell's needs at any given moment. These structures do not just provide a static framework but actively participate in the cell's life by facilitating processes such as the intracellular movement of vesicles, organelles, and even contributing to the cell's motile capabilities.