Facilitated diffusion and active transport
Facilitated diffusion is the movement of large particles (that cannot otherwise move across the cell membrane) from an area of higher concentration to an area of lower concentration with the help of trans-membrane proteins.
Active transport is the movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration using ATP energy. this may occur with large particles that cannot move across the cell membrane or small ones that can but don't due to the concentration gradient.
