Final answer:
The plasma membrane is a thin lipid bilayer that surrounds the cell, while the outer membrane is thicker and found in specific cell types. The thickness of the plasma membrane affects the function of transporters and porins, with a thicker membrane slowing down the diffusion rate and a thinner membrane allowing for a higher rate of diffusion.
Step-by-step explanation:
The plasma membrane is a thin lipid bilayer (6 to 8 nanometers) that surrounds the cell and separates the inside from the outside. In contrast, the outer membrane is a component of some specific cell types, such as gram-negative bacteria. The outer membrane is thicker compared to the plasma membrane and is composed of lipopolysaccharides, phospholipids, and porins.
The thickness of the plasma membrane affects the function of transporters and porins. A thicker membrane would make it more difficult for substances to pass through, slowing down their diffusion rate. On the other hand, the thinner plasma membrane allows for a higher rate of diffusion due to the increased surface area.