When
a channel is opened with a conformational switch, it is open to both
environment simultaneously (extracellular and intracellular); channels
are either in open state or closed state.
Pores
are continuously open to these both environment, because they do not
undergo conformational changes
They are always open.
Carrier Protein
Pathway
in a carrier protein is not open smiltaneously to the both environment.
Either its inner gate is open, or outer gate is open, or both gates are
closed.
Carrier has binding sites, but porins and channel proteins have not.
When a channel is opened, thousands to millions of ions can pass through the membrane in one time, but only one or a small amount of molecules can pass through a carrier molecule.
