Active transport occur in the uphill direction where passive transport occur in the downhill direction this is the principle comparison between passive transport and active transport.
Passive transport involves simple transport mechanism such as diffusion,osmosis and facilitated diffusion that help in the transport of molecule across the membrane from high concentration region to the region of low concentration untill equilibrium is reached.No additional energy is required to carry out passive transport. oxygen, carbon dioxide,water, glucose molecule are transported by passive transport mechanism.
Active Transport involves various ion channels which helps in the movement of molecules from low concentration region to the high concentration region .Additional energy in form of ATP is required to stimulate the active transport. Various ions such as Na+,K+, Ca2+, amino acids are transported by active transport.