Cytoskeleton

Eukaryotic cells have a wide variety of distinct shapes and internal organizations. Cells are capable of changing their shape, moving organelles, and in many cases, move from place to place. This requires a network a protein filaments placed in the cytoplasm known as the cytoskeleton.

The two most important protein filaments are called the actin filaments and the microtubules. The actin is responsbile for contraction (like in muscles) and the microtubules are for structural strength.