What are the extensions of the membrane that engulf bacteria called?

The extensions of the membrane that engulf bacteria are referred to as pseudopods. Pseudopodia are temporary protrusions of the cell membrane formed during the process of phagocytosis, where a cell, such as a type of immune cell, extends its membrane around a particle or pathogen to engulf it. This process is crucial for immune responses, allowing cells to remove pathogens and debris from the body.

While flagella, cilia, and filopodia serve important functions in cellular movement and sensing, they do not engage in the engulfing process like pseudopods do. Flagella are long, whip-like structures that propel cells through their environment. Cilia are shorter protrusions that often work in a coordinated manner to move substances along the surface of cells. Filopodia are slender, finger-like extensions that can help in sensing the environment and facilitating movement but do not directly function in the engulfment of particles. Thus, pseudopods are specifically adapted for phagocytosis, demonstrating their critical role in immune defense mechanisms.