Plasma membrane allows movement of only selected molecules across it, so it is called selectively permeable membrane . For instance, it permits the entry of gases through diffusion and water through osmosis. Larger molecules may pass through the plasma membrane by an active process. The plasma membrane is impermeable to certain other materials. The plasma membrane is called a selectively permeable membrane because it relatively allows the movement of substances from the inside of the cell to the outside and vice-versa. This selectivity depends on the requirements of the cell and the substances present in the surroundings of the cell. Conclusion: Therefore, the plasma membrane is called a selectively permeable membrane because it selectively allows certain molecules to enter or exit the cell while blocking others, thus regulating the internal environment of the cell. --- The cell membrane or plasma membrane is known as a selectively permeable membrane because it regulates the movement of substances in and out of the cell . This means that the plasma membrane allows the entry of only some substances and prevents the movement of some other materials.
