Convoluted invaginations of the cell membrane form specialized structures called mesosome which function in the formation of cross-wall during cell division。

膜卷曲，内陷可形特有的结构，称介体。其功能与裂有关。

The process involves extension and invagination of the plasma membrane to form small vesicles in pinocytosis (pinocytotic vesicles) or vacuoles in phagocytosis (food vacuoles).

内吞过程涉及到膜的延伸和内陷。