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What electron microscope technique is well suited for capturing subunit structures of high-molecular weight aggregates like viruses, ribosomes, multisubunit enzymes, and protein complexes? The specimen in the resulting micrograph stands out because they

are brighter than the viewing screen.
A) Whole-mount positive staining
B) Whole-mount negative staining
C) Plastic section shadow casting
D) Freeze fracture ñ freeze etch methodology
E) Scanning electron microscopy

1 Answer

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Final answer:

Whole-mount negative staining is the electron microscopy technique most suited for viewing subunit structures of high-molecular weight aggregates, resulting in specimens that appear brighter on a dark background. It is part of the electron microscopy techniques that offer high magnification and resolution, such as TEM and SEM, for studying detailed cell structures.

Step-by-step explanation:

The electron microscope technique that is well suited for capturing the high-molecular weight aggregates like viruses, ribosomes, multisubunit enzymes, and protein complexes is B) Whole-mount negative staining. This technique involves preparing the specimen by applying a heavy metal stain that surrounds but does not penetrate the specimen.

The result is a micrograph where the specimens appear brighter against the dark background of the stained viewing screen, making it an effective method for examining the detailed subunit structure of these aggregates. Electron microscopy encompasses various techniques, including the transmission electron microscope (TEM) and the scanning electron microscope (SEM).

TEM operates by passing electrons through the specimen and allows very high magnifications and resolution details as small as 0.1 nm, effectively used to analyze the ultrastructure of cells and their components. On the other hand, SEM magnifies the surface structures of specimens by reflecting electrons from them, revealing intricate details of tissue surfaces and cellular components.

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