Anatomy and Physiology Question?

Question

What is the main difference between facilitated diffusion and active transport?

Answer 1

In facilitated diffusion, the substance can only move down its concentration gradient from higher to lower concentrations. In active transport, a substance can be concentrated on one side of the membrane, and can move up its concentration gradient. Active transport, though, requires some external energy source (ATP or the concentration gradient of another molecule or ion) while facilitated diffusion is spontaneous on its own.