Why are active transport and diffusion different?

Active transport is the movement of molecules, usually against the concentration gradient (going from low concentration into a higher concentration), and it requires energy. Diffusion is the movement of molecules down the concentration gradient. In diffusion, the molecules can move from place to place by themselves and since they are all moving, the distribution eventually becomes equal (molecules have spread from a high concentration to a low concentration and created an equilibrium). In active transport, the molecules are being moved by a protein. The protein needs energy to shift molecules but the energy put in means that the concentration of the molecule on either side does not matter.