Integral and peripheral membrane proteins

Integral Membrane Proteins

These are proteins directly linked to the plasma membrane of cells ; they do not have  intermediate molecules between them and the plasma membranes. They are also considered as proteins that fully pass through the membrane (carrier proteins and channel proteins).

Peripheral Membrane Proteins

These proteins are connected to the plasma membrane through intermediate molecules (even integral proteins) or proteins attached to only one side of the membrane; do not pass through the membrane.