The term cyclosis refers to the streaming of cytoplasm inside a living cell. This motion enables materials to reach all parts of a cell including: oxygen and nutrients. There is a protein called actin, found in all eukaryotic cells which is part of the cytoskeleton. It is along these actin filaments that cytoplasmic streaming occurs in the cell's cytoskeleton. Actin is a highly conserved protein among most species which means that it serves an important function in terms of movements within cells and in muscle fibers. In plant cells, cytoplasmic streaming enables chloroplasts to move around enabling them to maximize light absorption necessary for photosynthetic activity.