Question 1

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

Accepted Answer

Eukaryotic cells have a nucleus containing DNA, whereas prokaryotic cells lack a nucleus.

Question 2

Which scientist is correctly matched with their major contribution to microbiology?

Accepted Answer

Louis Pasteur – Disproved spontaneous generation using the swan-neck flask experiment.

Question 3

A hospital patient develops an infection after surgery, despite the use of gloves and sterilized instruments. Which of the following best explains how this could occur?

Accepted Answer

The infection was likely caused by a healthcare-associated infection (HAI) due to a lapse in aseptic technique.

Question 4

Which of the following best describes Koch’s first postulate?

Accepted Answer

The suspected pathogen must be found in all cases of the disease and absent from healthy individuals.

Question 5

Which of the following is an example of bioremediation?

Accepted Answer

Using bacteria to clean up an oil spill in the ocean.

Question 6

A scientist observes that a certain bacterium is present in sick patients but not in healthy individuals. According to the scientific method, what is the next logical step?

Accepted Answer

Formulate a hypothesis about the bacterium causing disease.

Question 7

Which of the following correctly lists the taxonomic hierarchy from broadest to most specific?

Accepted Answer

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

Question 8

Which of the following is the correct way to write the scientific name for the bacterium that causes tuberculosis?

Accepted Answer

$$Mycobacterium tuberculosis$$

Question 9

Which of the following best describes a mutualistic relationship between a microbe and its host?

Accepted Answer

Both the microbe and the host benefit from the relationship.

Question 10

What is the primary function of the normal microbiota in the human gut?

Accepted Answer

To aid in digestion and protect against pathogenic microbes.

Question 11

A patient is prescribed broad-spectrum antibiotics and subsequently develops a yeast infection. What is the most likely explanation for this outcome?

Accepted Answer

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

Question 12

Which of the following best describes a biofilm?

Accepted Answer

A community of microorganisms attached to a surface and embedded in extracellular polymeric substances (EPS).

Question 13

Which of the following stains would be most appropriate to visualize bacterial endospores?

Accepted Answer

Endospore stain

Question 14

A microbiologist wants to distinguish between Gram-positive and Gram-negative bacteria. Which staining technique should they use, and what is the expected result for Gram-negative bacteria?

Accepted Answer

Gram stain; Gram-negative bacteria appear pink.

Question 15

Which type of microscopy would be best for viewing the detailed internal structures of a bacterial cell?

Accepted Answer

Transmission Electron Microscopy (TEM)

Question 16

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

Accepted Answer

It increases the refractive index between the lens and the specimen, reducing light refraction and improving resolution.

Question 17

Which of the following best explains why acid-fast staining is used in clinical microbiology?

Accepted Answer

To identify bacteria with cell walls rich in mycolic acid, such as $$Mycobacterium$$ species.

Question 18

A sample contains both $$E. coli K-12 $$and $$E. coli O157$$:H7. What does the difference in their names indicate?

Accepted Answer

They are different strains of the same species.

Question 19

Which of the following is a correct statement about the three domains of life?

Accepted Answer

The three domains are Bacteria, Archaea, and Eukarya.

Question 20

A researcher is using a dark-field microscope to observe bacteria. What is the main advantage of this technique?

Accepted Answer

It increases contrast, allowing visualization of live, unstained specimens against a dark background.

Chapter 1: Introduction to Microbiology – Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards