Question

Negative staining method is used for examining very small objects. It is generally used in \(\underline{\hspace{2cm}}\)

• A. TEM
• B. SEM
• C. Confocal Microscopy
• D. ESEM

Hint:

Think "negative" means staining the background, not the object itself. This method is perfect for seeing the outline or silhouette of tiny things like viruses, and it requires the "through-the-sample" view of a TEM.

Answer 1

The Correct Option is A

Step 1: Core Idea:
The task is to determine the microscopy type that utilizes negative staining.

Step 2: Elaboration:
Negative staining involves suspending a sample in an electron-dense solution (e.g., uranyl acetate) to create a dark background. This highlights unstained specimens, such as viruses or bacteria, by contrasting their size and surface features. Since this technique depends on electron scattering differences, it's used with Transmission Electron Microscopy (TEM).
\[\begin{array}{rl} \bullet & \text{SEM and ESEM examine surface structures and don't use negative staining.} \\ \bullet & \text{Confocal Microscopy is a fluorescence-based light microscopy, unrelated to this staining method.} \\ \end{array}\]

Step 3: Conclusion:
TEM (Transmission Electron Microscopy) commonly employs negative staining.