Question

In cell transport the difference between permeable transport and bulk transport relates to

• A. Structure of molecules allowed to pass through
• B. Solvent system as well as structure of molecules are applicable
• C. Solvent system is applicable
• D. Molecular weight of atoms to pass through

Answer 1

The correct option is A Structure of molecules allowed to pass through

In active transport, the substrate moves through the membrane of the cell against a concentration gradient.

In passive transport, the movement of molecules is directional, i.e. the solute molecules move from higher concentration region to lower concentration region whereas the solvent moves from a region of low solute concentration to a region of higher solute concentration to maintain equilibrium.

During bulk transport, the large molecules cross the membrane in bulk. In this type of transport, the cell takes in or out a large quantity of material packed in vesicles and the vesicle is transported. Depending on the direction of movement, bulk transport can be exocytosis or endocytosis. The figure below shows bulk transport.

All the three methods are related to passage of molecules, hence option A is correct.