Question

Differentiate between selectively permeable and semi-permeable membranes.

Answer 1

Hint: Semipermeable membrane permits only some particles to undergo depending on their size, whereas the selectively permeable membrane "chooses" what passes through and it does not depend on the size.

Complete answer:
The differentiation between selectively permeable and semipermeable membrane is -

Semipermeable membrane	Selectively permeable membrane
It does not allow solutes to pass through it.	It allows selected solutes to pass through it to a limited extent.
It acts as an ideal partition between two osmotically active solutions or between an answer and its pure solvent.	It acts as an imperfect partition with the result even plasmolyzed protoplasts get deplasmolysed automatically even kept within the same hypertonic solution.
It permits entry of only one solvent.	It permits entry of both solvents and to a selected extent solutes.
It doesn't exist within the biological word e.g. cellphane, collodion.	Almost all biological membranes are selectively permeable.
This type of membrane is used in dialysis maintenance of turgidity and measurement of osmotic potential.	It is useful in maintaining turgidity while retaining the ability to absorb solutes.
Example- egg membrane, parchment membrane, and tonoplast.	Example- plasmalemma.

Additional Information: The plasma membrane is named as a selectively permeable membrane because it permits the movement of only certain molecules in and out of the cells. Not all molecules are liberal to diffuse. If the plasma membrane breaks down then molecules of some substances will freely move in and out of the cells.

Note:
The diffusion of water through a selectively permeable membrane is called osmosis. Other types of semipermeable membranes are cation exchange membrane (CEM), charge mosaic membrane (CMM), bipolar membrane (BPM), anion exchange membrane (AEM), and proton exchange membrane (PEM).