Simple diffusion is not carrier mediated
transport hence do not follow saturation
kinetics.


◦ Facilitated diffusion, primary active transport,
and secondary active transport all involve
integral membrane proteins and are called
carrier-mediated transport.
◦ All carrier-mediated transport system follow
saturation kinetics
◦ The figure shows that as the concentration
of the diffusing substance increases, the rate
of simple diffusion continues to increase
proportionately, but in the case of facilitated
diffusion, the rate of diffusion cannot rise
greater than the transport maximum (Tm).
Tm is analogous to maximum velocity
(Vmax) level in enzyme kinetics