Question

Discuss the following statement in terms of speed, mechanism, regulation and specificity of transport: “The differences between a channel and a transporter are like the differences between a bridge and a ferry."

Answer 1

The given statement:

"The differences between a channel and a transporter are like the differences between a bridge and a ferry."

SPEED:

The channel has a higher transport rate than the transporter. This is because molecules flow quickly through a channel. People can cross quickly through a bridge rather than a ferry where it takes time to get on a ferry, cross, and then get off of it.

MECHANISM:

The channel has a fixed position like a bridge. There is no change in the conformation of the channel during transport. It just acts as a passageway for the molecules and ions to pass through it, just like a bridge. However, the transporter is not fixed in one place. It binds to a molecule, changes the conformation, and flips to the other side and releases the molecules into the cytosol, just like how a ferry carries people from one side to the other.

REGULATION:

Entrances of bridges can be altered to exclude large-sized trucks or vehicles. Channels allow only selective molecules to pass. Ferries, only when fully loaded, will move to the other side. In the same way, transporters, when fully bind to the required number of molecules, will be ready for transport.

SPECIFICITY:

Channels transport ions and water-soluble molecules. Transporters can move molecules that can be water-soluble or water-insoluble molecules. Bridges allow all sorts of vehicles that can fit the size of the bridge and cross it. Ferries can only carry people and specific loads to transport them across to the other side. It cannot carry loads heavier than a particular limit. Likewise, transporters only bind to a specific number of selected molecules.