Final answer:
Peripheral membrane proteins are attached to the cell membrane with weak bonds and can be easily detached. They are located either on the cytoplasmic or extracellular side of the membrane, where they participate in myriad functions, including enzymes, structural support, or cell recognition.
Step-by-step explanation:
The question refers to two different types of proteins associated with the cell membrane: peripheral membrane proteins and other proteins that are entirely outside the bilayer. Peripheral membrane proteins are those that are attached to the cell membrane by relatively weak bonds and can be easily solubilized due to their loose association with the membrane. They can be found on either the cytoplasmic side or the extracellular side of the membrane, where they can serve as enzymes, structural attachments, or in cell recognition.
These proteins, alongside integral proteins, are crucial for various cellular functions, including maintaining the structural integrity of the cell, enabling cell signalling pathways, and recognizing other cells. The body can distinguish between its own proteins and those from foreign pathogens due in part to these proteins.