$$\text{Total Magnification} = \text{Objective Lens} \times \text{Ocular Lens}$$

Question 1

Which unit is most appropriate for measuring the diameter of a typical bacterial cell?

Accepted Answer

Micrometer ($$1\ \mu m)$$

Question 2

In a compound light microscope, what is the formula for calculating total magnification?

Accepted Answer

$$	ext{Total Magnification} = 	ext{Objective Lens} 	imes 	ext{Ocular Lens}$$

Question 3

Which microscopy technique is best suited for viewing live, unstained microorganisms such as Treponema pallidum?

Accepted Answer

Darkfield microscopy

Question 4

What is the primary advantage of using immersion oil with a compound light microscope?

Accepted Answer

It prevents light from refracting and improves resolution.

Question 5

Which type of microscopy uses two beams of light and prisms to produce brightly colored, three-dimensional images?

Accepted Answer

Differential interference contrast (DIC) microscopy

Question 6

A researcher wants to study the surface structure of a virus at high resolution. Which microscope should they use?

Accepted Answer

Scanning electron microscope (SEM)

Question 7

Which microscopy technique allows for single-molecule tracking and super-resolution imaging in bacteria?

Accepted Answer

Super-resolution light microscopy

Question 8

What is the main difference between a basic dye and an acidic dye in bacterial staining?

Accepted Answer

Basic dyes have a cationic chromophore; acidic dyes have an anionic chromophore.

Question 9

During Gram staining, what color will gram-negative bacteria appear after the application of safranin?

Accepted Answer

Pink/red

Question 10

Which staining technique is specifically used to identify bacteria with waxy cell walls, such as Mycobacterium?

Accepted Answer

Acid-fast stain

Question 11

A scientist needs to visualize the internal structure of a cell slice at nanometer resolution. Which microscope should they use?

Accepted Answer

Transmission electron microscope (TEM)

Question 12

Which microscopy technique uses sound waves to study cells attached to surfaces, such as arterial plaque or bacterial biofilms?

Accepted Answer

Scanning acoustic microscopy (SAM)

Question 13

What is the purpose of a mordant in staining procedures?

Accepted Answer

To hold the stain or coat the specimen, enlarging it

Question 14

Which microscopy technique is most suitable for tracking the activity of living cells up to 1 millimeter deep in real time?

Accepted Answer

Two-photon microscopy

Question 15

What is the resolving power of a compound light microscope, and what does it mean?

Accepted Answer

$$0.2\ \mu m$$; it can distinguish two points at least $$0.2\ \mu m$$ apart

Question 16

Which of the following is NOT a use for fluorescence microscopy?

Accepted Answer

Studying cell surface structures at atomic detail

Question 17

What is the main difference between scanning tunneling microscopy (STM) and atomic force microscopy (AFM)?

Accepted Answer

STM uses a tungsten probe and can resolve features as small as an atom; AFM uses a metal-and-diamond probe for near atomic detail

Question 18

Which special stain would you use to visualize the presence of a bacterial capsule?

Accepted Answer

Capsule stain

Question 19

Why are Gram stains most consistent when used on young, actively growing bacteria?

Accepted Answer

Older bacteria may have damaged or altered cell walls, affecting stain uptake

Question 20

A clinical lab technician needs to rapidly identify Mycobacterium tuberculosis in a patient sample. Which staining method and dye should they use?

Accepted Answer

Acid-fast stain with carbolfuchsin

Microscopy: Principles, Types, and Applications in Microbiology

Study Guide - Practice Questions