What is Passive Transport?
Passive Transport: Specialized proteins called permeases also move specific substances across the cell membrane in a process called carrier transport. If these molecules function without requiring chemical energy, the passive transport is called facilitated diffusion. Substances cross the cell membrane in the same direction as they would by diffusion.
Another passive transport mechanism consists of gated channels, proteins that allow certain substances to cross the cell membrane, either permanently or following a chemical or electrical stimulus. An example of passive transport: glucose enters red blood cells about 100 times faster than would be expected from simple diffusion. This process apparently does not require energy.