Final answer:
The advantage of images produced by freeze-fracture followed by freeze-etching over images from freeze-fracture alone is that they reveal both the external and internal surfaces of the cell membrane, offering a detailed and three-dimensional view.
Step-by-step explanation:
The direct answer to the question is C:
Freeze-fracturing and freeze-etching are techniques used in electron microscopy to study cell membranes and their structural details. Freeze-fracture involves rapidly freezing the cell and then fracturing it to reveal structures along the plane of weakness in the lipid bilayer. This allows for the observation of the internal features of the cell membrane. Freeze-etching is an additional step where the fractured surface is coated with a thin layer of metal, and then the ice is etched away by sublimation. Freeze-fracture is a technique that involves freezing isolated membranes and then splitting them along the interior of the membrane. This technique allows for the visualization of the internal and external surfaces of the cell membrane, providing a more complete understanding of its structure.
This exposes and highlights more surface details, providing a three-dimensional view of both the inner and outer surfaces of the membrane. The method particularly elucidates the mosaic organization and asymmetry of the plasma membrane, such as integral proteins and carbohydrate components like the oligosaccharides on glycoproteins, which are distinctive in the external layer of the plasma membrane.