Membrane Permeability - Practice Questions & MCQ

• Permeability can be defined as the property of a membrane to allow transport of a given substance across it.
• It depends on:
  • The size of pores in the plasma membrane
  • The size and charge of the molecules of the given substance

Based on the permeability, the membranes can be of following types:

• Permeable membranes: If a given substance passes readily across the membrane.
• Impermeable membranes: If a given substance cannot pass through the membrane.
• Semipermeable membranes: If the membrane allows only water molecules to pass through it and solutes and not allowed at all.
• Selectively permeable membranes: If the membranes allow some selected solute molecules to pass through it along with water molecules. These are also called differentially permeable membranes. Such membranes operate in the biological systems.

Note: 

• The semipermeable membranes are used for the operation of osmosis.
• The selectively permeable membranes are used for the operation of diffusion.