Question 1

Which of the following statements best describes the difference between prokaryotic and eukaryotic cells?

Accepted Answer

Prokaryotic cells lack a nucleus, while eukaryotic cells have a nucleus.

Question 2

Which of the following is NOT considered a living microbe studied in microbiology?

Accepted Answer

Viruses

Question 3

A scientist observes that maggots only appear on meat when flies can access it. Which theory does this observation support?

Accepted Answer

Biogenesis

Question 4

Which scientist is credited with disproving spontaneous generation using an S-necked flask experiment?

Accepted Answer

Louis Pasteur

Question 5

According to Koch’s postulates, what must be true for a microbe to be identified as the cause of a disease?

Accepted Answer

The microbe must be isolated from a diseased organism and grown in pure culture.

Question 6

Which of the following is an example of an opportunistic pathogen?

Accepted Answer

A microbe that causes disease only when the host is immunocompromised.

Question 7

Which of the following is a correct sequence in the taxonomic hierarchy from broadest to most specific?

Accepted Answer

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 8

Which of the following best describes mutualism in host–microbe interactions?

Accepted Answer

Both the microbe and the host benefit from the relationship.

Question 9

Why are biofilms particularly problematic in medical settings?

Accepted Answer

Biofilms are resistant to antibiotics and immune responses.

Question 10

Which of the following is a function of the normal microbiota in humans?

Accepted Answer

Training the immune system and aiding digestion

Question 11

A woman develops a vaginal yeast infection after taking antibiotics for a urinary tract infection. What is the most likely explanation?

Accepted Answer

The antibiotics disrupted the normal microbiota, allowing opportunistic pathogens to grow.

Question 12

Which of the following best describes the scientific method?

Accepted Answer

A process that involves observation, hypothesis, experimentation, and conclusion.

Question 13

Which of the following is true about Gram-positive bacteria?

Accepted Answer

They retain the crystal violet stain and appear purple.

Question 14

What is the purpose of a mordant in a staining procedure?

Accepted Answer

To fix or trap the dye on or inside the specimen

Question 15

Which microscopy technique would be best for visualizing unstained, live specimens?

Accepted Answer

Dark field microscopy

Question 16

If a compound light microscope has an ocular lens of 10x and an objective lens of 40x, what is the total magnification?

Accepted Answer

$$10 	imes 40 = 400$$

Question 17

Which of the following is a distinguishing feature of acid-fast bacteria?

Accepted Answer

Waxy cell walls rich in mycolic acid

Question 18

Which of the following is a real-world application of bioremediation?

Accepted Answer

Using microbes to degrade petroleum oil spills into $$CO_2$$

Question 19

Why is immersion oil used with the 100x objective lens in light microscopy?

Accepted Answer

To increase the refractive index and reduce light scattering

Question 20

Which of the following best explains why only about 2% of bacteria can be cultured in the laboratory?

Accepted Answer

Most bacteria require complex growth environments not easily replicated in the lab.

Introduction to Microbiology: Core Concepts and Methods

Study Guide - Practice Questions