Question

Parchment paper is
A) Permeable membrane
B) Impermeable membrane
C) Semipermeable membrane
D) None of the above

Answer 1

Parchment paper allows transport of certain molecules or ions to pass through by diffusion i.e. selective movement of molecules across the cells. It regulates the movement of flow.

Complete answer:
Parchment paper is a semipermeable membrane. In living systems, this system is also referred to as a differentially or selectively permeable membrane where no solute particle can directly diffuse through the membrane, and the inflow of solutes is regulated with the help of proteins (either by channel proteins or carrier proteins).

Additional Information:
Permeability is the degree of diffusion of gases, liquids, and dissolved substances through a membrane, and this ability of a substance to pass through a membrane is known as its permeability. A membrane can be freely permeable for one substance, moderately permeable for the second one, and maybe completely impermeable for the third one.
Based on the permeability, the following types of membranes have been recognized:
- Freely permeable membrane: The membrane which allows free passage of various substances across the membrane. Example: Cell wall.
- Impermeable membrane: The membrane which does not allow any kind of movement through it. Example: cutinized cell wall.
- Semi-permeable membrane: The membrane which allows passage of only solvent particles to pass through it. It does not allow the movement of solute particles. Example: egg membrane, animal bladder, parchment membrane. Artificial membranes are also present.
- Selectively permeable membrane or differentially permeable membrane: The membranes which allow passage of some selected molecules (of solute and solvent) to pass through it. Example: Most of the biological membranes, such as cell membranes, tonoplast (vacuolar membrane), and the membrane surrounding the subcellular organelles are selectively permeable.
So, the correct answer is ‘semipermeable membrane’.

Note:
Selectively permeable membranes give differential treatment to different kinds of molecules, some molecules move very rapidly, some move very slowly, while rest others do not move at all. A nonliving selectively permeable membrane is cellophane.