Compare various transport processes.

$\Rightarrow$ It is clear that proteins in the membrane are responsible for facilitated diffusion and active transport.
$\Rightarrow$ Thus, they show common characteristics of being highly selective.
$\Rightarrow$ They are liable to saturate, respond to inhibitors, and are under hormonal regulation.
$\Rightarrow$ However, diffusion, whether facilitated or not, takes place only along a gradient and does not use energy.

Property	Simple Diffusion	Facilitated Transport	Active Transport
Requires special membrane proteins	No	Yes	Yes
Highly selective	No	Yes	Yes
Transport saturates	No	Yes	Yes
Uphill transport	No	No	Yes
Requires $ATP$ energy	No	No	Yes