Question 1

Which property of electromagnetic radiation is most directly responsible for the resolving power of a microscope?

Accepted Answer

Wavelength

Question 2

A microbiologist is using a compound light microscope to observe bacteria. She switches from air to immersion oil under the objective lens. What is the primary reason for this change?

Accepted Answer

To reduce light refraction and improve resolution

Question 3

Which formula best describes the relationship between resolution ($d$), wavelength ($\lambda$), and numerical aperture ($NA$) in light microscopy?

Accepted Answer

$d = \frac{\lambda}{2NA}$

Question 4

Which type of microscope would be most appropriate for visualizing the surface details of a virus particle?

Accepted Answer

Scanning electron microscope (SEM)

Question 5

A scientist wants to identify a bacterial pathogen in a patient sample using a method that relies on antigen-antibody reactions. Which test should she use?

Accepted Answer

Serological test

Question 6

Which staining technique would be most useful for distinguishing between Mycobacterium tuberculosis and other bacteria in a sputum sample?

Accepted Answer

Acid-fast stain

Question 7

Why are basic dyes more commonly used than acidic dyes for staining bacterial cells?

Accepted Answer

Bacterial cells are negatively charged and attract basic dyes

Question 8

Which of the following is NOT a major goal of modern taxonomy?

Accepted Answer

Grouping organisms solely by their ability to interbreed

Question 9

A dichotomous key is used in microbiology for which purpose?

Accepted Answer

To identify microorganisms based on a series of paired statements

Question 10

Which of the following statements about fluorescence microscopy is TRUE?

Accepted Answer

It uses UV light to excite specimens, which then emit visible light

Question 11

Which taxonomic domain includes organisms with peptidoglycan in their cell walls?

Accepted Answer

Bacteria

Question 12

A laboratory technician is using a Gram stain to differentiate bacteria. What is the primary structural feature being assessed?

Accepted Answer

Thickness of the peptidoglycan layer

Question 13

Which of the following is a correct sequence for the five-kingdom classification system?

Accepted Answer

Animalia, Plantae, Fungi, Protista, Prokaryotae

Question 14

Which of the following is a biochemical test used to identify bacteria?

Accepted Answer

Ability to ferment lactose

Question 15

A scientist is analyzing the G+C content of a bacterial DNA sample. What is the purpose of this analysis?

Accepted Answer

To classify and identify the microbe

Question 16

Which of the following best describes the chromophore in a dye used for staining?

Accepted Answer

The colored portion of the dye

Question 17

Which of the following is a limitation of light microscopes compared to electron microscopes?

Accepted Answer

Light microscopes cannot resolve structures closer than 200 nm

Question 18

A researcher uses phage typing to identify a bacterial strain. What is the underlying principle of this method?

Accepted Answer

Phages infect only specific bacterial hosts

Question 19

Which of the following increases both contrast and resolution in microscopy?

Accepted Answer

Staining specimens

Question 20

A student observes a protozoan under a microscope and identifies it based solely on its morphology. Which taxonomic characteristic is being used?

Accepted Answer

Physical characteristics

Microscopy: Principles, Techniques, and Applications in Microbiology

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