Question 1

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

Accepted Answer

Prokaryotic cells lack a nucleus and are always unicellular, while eukaryotic cells have a nucleus and can be unicellular or multicellular.

Question 2

Louis Pasteur disproved the theory of spontaneous generation by using which experimental setup?

Accepted Answer

An S-necked flask that allowed air in but prevented microbial contamination.

Question 3

Which of Koch’s postulates is violated if a suspected pathogen cannot be cultured in the laboratory?

Accepted Answer

The organism must be isolated from the diseased host and grown as a pure culture.

Question 4

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

Accepted Answer

Candida albicans causing a yeast infection after antibiotic therapy.

Question 5

Which scientist is credited with introducing hand washing to reduce childbed fever in hospitals?

Accepted Answer

Ignaz Semmelweis

Question 6

A scientific law is best defined as:

Accepted Answer

A precise statement or mathematical formula that predicts a specific occurrence.

Question 7

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

Accepted Answer

Both the microbe and the host benefit from the relationship.

Question 8

Why are biofilms particularly problematic in healthcare settings?

Accepted Answer

Biofilms are more resistant to antibiotics and immune system defenses.

Question 9

Which staining technique would you use to differentiate between bacteria with waxy cell walls and those without?

Accepted Answer

Acid-fast stain

Question 10

What is the main purpose of using immersion oil with a 100x objective lens in light microscopy?

Accepted Answer

To match the refractive index of glass and prevent light scattering, improving resolution.

Question 11

Which of the following is a correct example of binomial nomenclature?

Accepted Answer

Escherichia coli

Question 12

A woman develops a vaginal yeast infection after taking antibiotics for a urinary tract infection. This is an example of:

Accepted Answer

A disruption in normal microbiota allowing an opportunistic pathogen to cause disease.

Question 13

Which of the following statements about Gram staining is correct?

Accepted Answer

Gram-positive cells retain the crystal violet-iodine complex and appear purple.

Question 14

Which part of the compound light microscope is responsible for sharpening light into a precise cone to illuminate the specimen?

Accepted Answer

Condenser lens

Question 15

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

Accepted Answer

Using microbes to clean up petroleum oil spills by metabolizing toxic substances into harmless intermediates.

Question 16

Which of the following best describes the role of normal microbiota in human health?

Accepted Answer

Normal microbiota train the immune system, produce vitamins, and help digest food.

Question 17

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 18

Which type of electron microscopy is best suited for visualizing the 3D surface structure of a microbe?

Accepted Answer

Scanning electron microscopy (SEM)

Question 19

A researcher observes a grouping of cells that developed from a single parent cell on an agar plate. What is this grouping called?

Accepted Answer

Colony

Question 20

Which formula correctly calculates the total magnification of a compound light microscope?

Accepted Answer

$Total\ Magnification = Objective\ Lens\ Magnification 	imes Ocular\ Lens\ Magnification$

Introduction to Microbiology: Basic Principles and Clinical Applications

Study Guide - Practice Questions