a) Simple Diffusion Mechanism

✓ Passive Transport Mechanism :

a) Simple Diffusion Transport Mechanism :

Simple transport mechanism is also refers as Passive Diffusion Transport Mechanism in a Microbial Cell or Simply Called as "Diffusion".

In simple Diffusion tranaport molecules move from higher concentration to lower one region of cell membrane and the rate of transportation is basically depends on size of gradient between transport from cells exterior and its interior.

Very small or tiny molecules can transports usually  such as #Water , #Oxygen & #Carbon dioxide move across membranes by simple diffusion transport mechanism.
Larger molecules , #ions & #Polar substances cannot cross membrane with this method.