Question 1

Which of the following statements 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

Which scientist is credited with disproving spontaneous generation through his S-necked flask experiment?

Accepted Answer

Louis Pasteur

Question 3

A patient develops a Clostridium difficile infection after taking antibiotics for a respiratory infection. This is most likely due to:

Accepted Answer

The antibiotics disrupting the normal microbiota, allowing opportunistic pathogens to thrive.

Question 4

Which of the following is NOT a step in Koch’s postulates?

Accepted Answer

The organism must be genetically sequenced and compared to known pathogens.

Question 5

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

Accepted Answer

Both the microbe and the host benefit from the relationship.

Question 6

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

Accepted Answer

Acid-fast stain

Question 7

A scientist observes purple cells after performing a Gram stain. What does this indicate about the bacterial cell wall?

Accepted Answer

The cells are Gram-positive and have a thick peptidoglycan layer.

Question 8

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

Accepted Answer

Producing vitamins and training the immune system

Question 9

Which of the following best explains why immersion oil is used with the 100× objective lens in light microscopy?

Accepted Answer

It increases the refractive index to match that of glass, reducing light scattering and improving resolution.

Question 10

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

Accepted Answer

Escherichia coli

Question 11

A hospital-acquired infection is also known as:

Accepted Answer

Nosocomial infection

Question 12

Which of the following best describes the purpose of a streak plate technique?

Accepted Answer

To isolate colonies of a specific microbe from a mixed culture

Question 13

Which of the following is a plausible consequence of disrupting the normal microbiota with broad-spectrum antibiotics?

Accepted Answer

Overgrowth of opportunistic pathogens such as Candida albicans

Question 14

Which of the following is NOT a type of light microscopy?

Accepted Answer

Scanning electron microscopy

Question 15

Which of the following best describes the difference between a scientific law and a scientific theory?

Accepted Answer

A law is a precise statement or mathematical formula that predicts a specific occurrence, while a theory explains how and why something occurs.

Question 16

Which of the following is the correct order of the taxonomic hierarchy from broadest to most specific?

Accepted Answer

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

Question 17

Which of the following best describes an opportunistic pathogen?

Accepted Answer

A microbe that causes disease only in a weakened host

Question 18

Which of the following is a correct statement about biofilms?

Accepted Answer

Biofilms are sticky communities that can be made up of single or diverse microbial species and are hard to penetrate.

Question 19

Which of the following is a function of a mordant in a staining procedure?

Accepted Answer

To fix or trap the dye on the treated specimen

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 that are difficult to replicate in the lab.

Introduction to Microbiology: Foundations, Methods, and Microbial Interactions

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