Question 1

Which of the following best describes the principle of resolution in microscopy?

Accepted Answer

The ability to see two objects as separate entities.

Question 2

A microbiologist observes a specimen using a light microscope with a 40X objective lens and a 10X ocular lens. What is the total magnification?

Accepted Answer

$40 	imes 10 = 400$

Question 3

Which type of microscope would be most appropriate for visualizing viruses, given their size?

Accepted Answer

Electron microscope

Question 4

Why is oil immersion used with high-power objective lenses in light microscopy?

Accepted Answer

To reduce light refraction and improve resolution.

Question 5

Which staining technique is used to differentiate between Gram-positive and Gram-negative bacteria?

Accepted Answer

Gram stain

Question 6

During Gram staining, what is the role of iodine?

Accepted Answer

It acts as a mordant to help the primary stain adhere to cells.

Question 7

Which of the following is a correct sequence of steps in the Gram staining procedure?

Accepted Answer

Crystal violet, iodine, alcohol, safranin

Question 8

A bacterium is observed to be purple after Gram staining. What does this indicate about its cell wall structure?

Accepted Answer

It has a thick peptidoglycan layer and no outer membrane.

Question 9

Which type of microscopy is best suited for observing live, unstained cells and their internal structures?

Accepted Answer

Phase contrast microscopy

Question 10

A sample is stained with malachite green and safranin. What structure is being identified?

Accepted Answer

Endospore

Question 11

Which of the following is NOT a characteristic of endospores?

Accepted Answer

They are easily destroyed by boiling water.

Question 12

Which classification level is the narrowest and most specific in the binomial system?

Accepted Answer

Species

Question 13

Which of the following statements about prokaryotes is TRUE?

Accepted Answer

They lack a nucleus and can be found in both extreme and non-extreme environments.

Question 14

A microbiologist wants to identify Mycobacterium tuberculosis in a sputum sample. Which staining technique should be used?

Accepted Answer

Acid-fast stain

Question 15

Which of the following best describes the function of a capsule stain?

Accepted Answer

It leaves the capsule unstained against a dark background.

Question 16

Which of the following is a correct match between organism and typical size unit?

Accepted Answer

Animals - millimeters

Question 17

Which of the following is a real-world application of fluorescence microscopy?

Accepted Answer

Visualizing organisms that emit light after being treated with a fluorescent dye

Question 18

A scientist performs DNA fingerprinting to identify a bacterial species. Which classification method is being used?

Accepted Answer

Nucleic acid analysis

Question 19

Which of the following is a correct statement about the binomial system of nomenclature?

Accepted Answer

It assigns each organism a genus and species name.

Question 20

Which microscope would be best for observing the three-dimensional structure of a cell surface at nanometer resolution?

Accepted Answer

Electron microscope

Microscopy, Staining, and Classification in Microbiology

Study Guide - Practice Questions