Determine the location of integral and peripheral proteins in the cell membrane.

• A. The integral proteins are loosely attached to the exterior or interior surfaces of the membrane, while the peripheral proteins are embedded within the lipid bilayer and can span across the membrane.
• B. The integral proteins are permanently attached to the exterior or interior surfaces of the membrane, while the peripheral proteins are spread within the lipid bilayer and can span across the membrane.
• C. The integral proteins are spread within the lipid bilayer and can span across the membrane, while the peripheral proteins are permanently attached to the exterior or interior surfaces of the membrane.
• D. The integral proteins are embedded within the lipid bilayer and can span across the membrane, while the peripheral proteins are loosely attached to the exterior or interior surfaces of the membrane.

Answer: (D)