Here's a breakdown:

* Diffusion: The natural movement of molecules from an area of high concentration to an area of low concentration. This is driven by the concentration gradient.

* Facilitated Diffusion: A type of passive transport (doesn't require energy) where molecules move across the cell membrane with the help of special proteins called transport proteins. These proteins act like channels or carriers, making it easier for certain molecules to pass through the membrane that would otherwise struggle to do so.

Types of Transport Proteins:

* Channel Proteins: These act like tunnels or pores, allowing specific molecules to pass through the membrane based on their size and charge.

* Carrier Proteins: These bind to the molecule they are transporting, changing shape to move the molecule across the membrane.

Key Points about Facilitated Diffusion:

* It's passive, meaning it doesn't require the cell to expend energy.

* It's specific, meaning each transport protein only facilitates the movement of certain molecules.

* It's saturable, meaning the rate of transport can reach a maximum if the concentration of the transported molecule is high enough.

Let me know if you have any other questions!