1. Amoeboid movement: This is a form of locomotion used by some cells, including amoebas and certain white blood cells. It involves extending projections of the cytoplasm called pseudopodia, which the cell uses to pull itself forward. This process relies on the cell's ability to rapidly change the shape of its cytoplasm by assembling and disassembling microfilaments, primarily composed of actin.
2. Endocytosis and Exocytosis: These processes are used by cells to transport large molecules and particles across the cell membrane.
* Endocytosis involves the cell engulfing material by forming an invagination of the plasma membrane, which then pinches off to form a vesicle containing the ingested material. This requires the cytoplasm to deform and change shape to enclose the material.
* Exocytosis involves the cell releasing material from within by fusing vesicles containing the material with the plasma membrane, causing the material to be expelled outside the cell. This process also requires changes in the shape of the cytoplasm as vesicles migrate to and fuse with the cell membrane.
Both processes rely on the cell's ability to reorganize its cytoskeleton and, therefore, its cytoplasm, to facilitate these movements.
