Question

why is plasma membrane is called semipermeable membrane

Answer 1

Plasma membrane called semipermeable membrane because it allow the materials to go in and come out of the cell but not all it allows only the benifitial materials .

Answer 2

The plasma membrane is called semi-permeable or selectively permeable membrane as it allows only the entry of certain substances, mostly solvent and gases through it and does not allow bigger substances to pass through it.

This property helps in the protection of the organelles of the cells from the outside environment as the plasma membrane allows selective entry and exit of molecules to and from the cell.