Positive Staining of Viruses MCQs Mock Test (30 MCQs)

Learn about positive staining methods for virus detection in clinical and research settings. This comprehensive guide covers:

✓ Principles of Positive Staining (dye-binding mechanisms)
✓ Key Techniques:

Immunohistochemistry (IHC) – Antibody-based detection
Immunofluorescence (IF) – Fluorescent tagging of viral antigens
Hematoxylin & Eosin (H&E) – Histopathological identification of viral inclusions
Giemsa Staining – Viral cytopathic effects in cell cultures
Electron Microscopy (EM) Stains – Heavy metal contrasting (e.g., uranyl acetate)

✓ Diagnostic Applications:

Herpesviruses (Cowdry type A inclusions)
Rabies (Negri bodies in neurons)
Cytomegalovirus (CMV) (Owl’s eye inclusions)
Respiratory viruses (RSV, Influenza)

✓ Comparison with Negative Staining (for EM visualization)
✓ Troubleshooting Common Staining Issues

Essential for virologists, pathologists, and clinical lab professionals working in infectious disease diagnostics.

Test your knowledge with 30+ MCQs on positive viral staining methods, covering:
◼️ Identification of viral inclusion bodies
◼️ Selection of appropriate staining techniques (IHC vs. IF vs. H&E)
◼️ Interpretation of stained samples
◼️ Common pitfalls and artifacts

Perfect for medical students, virology researchers, and lab technicians preparing for certification exams.

0 votes, 0 avg

Microbiology Department

Positive staining of Viruses MCQs Mock Test

Perfect for medical students, virology researchers, and lab technicians preparing for certification exams.

Read Full Article: Positive staining of Viruses 50 FAQ and 30 MCQs

1 / 30

Category: Clinical Laboratory

What is the primary purpose of positive staining in electron microscopy?

To dissolve viral structures

To reduce electron density

To make the background dark

To enhance the contrast of virus particles

2 / 30

Category: Clinical Laboratory

What magnification is typically used for virus observation?

100x–1,000x

1,000x–5,000x

1,000,000x

10,000x–100,000x

3 / 30

Category: Clinical Laboratory

Why is uranyl acetate hazardous?

It is edible

It is radioactive and toxic

It is harmless

It improves eyesight

4 / 30

Category: Clinical Laboratory

How should grids be dried before TEM observation?

Using a hairdryer

Freezing in liquid nitrogen

Heating at 100°C

Air-drying or blotting with filter paper

5 / 30

Category: Clinical Laboratory

Why is uranyl acetate commonly used in positive staining?

It binds to proteins and nucleic acids✔

It binds to lipids only

It fluoresces under light

It dissolves viral envelopes

6 / 30

Category: Clinical Laboratory

Which of the following is NOT a common stain used in positive staining?

Osmium tetroxide

Methylene blue

Uranyl acetate

Lead citrate

7 / 30

Category: Clinical Laboratory

Why is fixation necessary before staining?

To reduce staining time

To make the virus fluorescent

To dissolve the virus

To preserve viral structure

8 / 30

Category: Clinical Laboratory

What is the first step in positive staining?

Staining with uranyl acetate

Immediate TEM observation

Sample purification and concentration

Fixation with glutaraldehyde

9 / 30

Category: Clinical Laboratory

Why must lead citrate staining be performed in a CO₂-free environment?

CO₂ reacts with lead citrate, causing precipitates

CO₂ makes viruses invisible

CO₂ improves resolution

CO₂ enhances staining

10 / 30

Category: Clinical Laboratory

How long should a grid be incubated in uranyl acetate for optimal staining?

30 seconds to 15 minutes

1 hour

24 hours

1 second

11 / 30

Category: Clinical Laboratory

Which technique preserves native virus structure better than positive staining?

PCR

Cryo-EM

Light microscopy

Gram staining

12 / 30

Category: Clinical Laboratory

What is a major advantage of positive staining?

It is simple and provides high-contrast images

It works only for bacteria

It provides functional data on viral replication

It does not require an electron microscope

13 / 30

Category: Clinical Laboratory

What is the correct concentration of uranyl acetate typically used?

10%

0.1%

14 / 30

Category: Clinical Laboratory

How does positive staining differ from negative staining?

Positive staining makes viruses appear light on a dark background

Both techniques produce the same results

Negative staining is not used in virology

Positive staining makes viruses appear dark on a light background

15 / 30

Category: Clinical Laboratory

What does a dark region in a positively stained TEM image represent?

Background

Unstained area

Artifacts

Electron-dense viral structures

16 / 30

Category: Clinical Laboratory

How should uranyl acetate waste be disposed of?

In designated radioactive/chemical waste containers

By burning it

In a regular trash bin

By flushing down the sink

17 / 30

Category: Clinical Laboratory

What future improvement is expected in positive staining?

No further advancements

Replacement with Gram staining

New stains and reduced artifacts

Elimination of TEM

18 / 30

Category: Clinical Laboratory

How is excess stain removed from the grid after staining?

By washing with ultra-purified water

By freezing the sample

By using a strong acid

By heating the grid

19 / 30

Category: Clinical Laboratory

What is the role of heavy metal salts in positive staining?

They make viruses invisible under TEM

They dissolve viral proteins

They prevent staining artifacts

They increase electron density for better contrast

20 / 30

Category: Clinical Laboratory

Can positive staining be combined with immunogold labeling?

Only for bacteria

No, they are incompatible

Only in light microscopy

Yes, for targeted protein visualization

21 / 30

Category: Clinical Laboratory

Which microscope is used to observe positively stained viruses?

Transmission Electron Microscope (TEM)

Light microscope

Scanning Electron Microscope (SEM)

Fluorescence microscope

22 / 30

Category: Clinical Laboratory

How does positive staining help in vaccine development?

By killing viruses

By making viruses invisible

By sequencing viral DNA

By providing structural details for antigen design

23 / 30

Category: Clinical Laboratory

Which stain is best for visualizing viral lipid envelopes?

Uranyl acetate

Methylene blue

Lead citrate

Osmium tetroxide

24 / 30

Category: Clinical Laboratory

What is the purpose of washing grids after staining?

To make the grid sterile

To dissolve the virus

To increase staining intensity

To remove excess stain and prevent artifacts

25 / 30

Category: Clinical Laboratory

Which factor can cause staining artifacts?

Excess stain or contamination

Proper washing

Using fresh uranyl acetate

Air-drying grids slowly

26 / 30

Category: Clinical Laboratory

Which staining method combines uranyl acetate, glutaraldehyde, and PVA?

Tokuyasu staining procedure (TSP)

Gram staining

Immunogold staining

Negative staining

27 / 30

Category: Clinical Laboratory

What is a limitation of positive staining?

It cannot visualize viral structures

It does not require heavy metals

It is faster than negative staining

It is sensitive to CO₂ and light

28 / 30

Category: Clinical Laboratory

Which viral structure is NOT typically visible with positive staining?

Spikes

Capsid

Viral RNA sequence

Envelope

29 / 30

Category: Clinical Laboratory

What precaution is necessary when using osmium tetroxide?

Work without gloves

No precautions needed

Use in an open room

Use in a fume hood

30 / 30

Category: Clinical Laboratory

Which virus has been studied using positive staining?

None of the above

Escherichia coli

HIV-1

Saccharomyces cerevisiae

If you want to download Certificates then Please Put your Name and Correct Email

Your score is

The average score is 0%

Read Full Article: Positive staining of Viruses 50 FAQ and 30 MCQs

Possible References Used

Shares0Share0 Tweet0 Pin0 LinkedIn0 Email0

Positive Staining of Viruses MCQs Mock Test (30 MCQs)

Free ASCP MLS Exam Practice Questions: Part 24 – Microbiology – Gram-Negative Bacilli Identification

Urine Eosinophils

Hematology MCQs

Qualitative or Quantitative Stool Fat Test

MCQs Mock Test for Lab Technicians and Technologists: Chapter 11

Pus Cells in Urine Test

Leave a Reply Cancel reply

Report a question

Related Posts

Leave a Reply Cancel reply