What's he difference between active and passive transport?

-Transporters for molecules and ions bind their substrates with high specificity, catalyze transport at rates well below the limits of free diffusion, and are saturable in the same sense as are enzymes: there is some substrate concentration above which further increases will not produce a greater rate of transport. -Passive transport Channels generally allow transmembrane movement of ions at rates that are orders of magnitude greater than those typical of transporters, approaching the limit of unhindered diffusion (tens of millions of ions per second per channel). Channels typically show some specificity for an ion, but are not saturable with the ion substrate, in contrast to the saturation kinetics seen with transporters.