Final answer:
Proteins in the fluid mosaic model of membrane structure are mostly embedded in the lipid bilayer and can span across it or be partially embedded, with carbohydrates on the membrane's exterior.
Step-by-step explanation:
According to the fluid mosaic model of membrane structure, the proteins of the membrane are mostly embedded in the lipid bilayer. The model proposes that the plasma membrane is composed of a phospholipid bilayer that is fluid and dynamic with proteins that can be integral or peripheral.
The integral proteins are the ones that are embedded within the lipid bilayer and can either span all the way through the bilayer or be partially embedded. Meanwhile, carbohydrates are attached to proteins and lipids on the membrane's outward-facing surface, forming glycoproteins and glycolipids.