what is semi permeable membrane explain in detail

Dear Student,

A semi permeable membrane is the one that allows certain molecules to pass through it while it does not allow others. Cell membrane is a semipermeable membrane.
Plasma membrane allows the passage of molecules to move in and out of the cell. It is also known as selectively permeable membrane because it allows the entry of selective(certain) substances while prevents the movement of some other materials.

Osmosis can be defined as the movement of water molecules across a semi permeable membrane, from a region of high concentration to a region of low concentration of water.

Regards