Question 1

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

Accepted Answer

Eukaryotic cells have a nucleus containing their genetic material, whereas prokaryotic cells lack a nucleus.

Question 2

Which scientist is correctly matched with their 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 microorganism must be found in all organisms suffering from the disease, but not in healthy organisms.

Question 5

A scientist observes that a certain bacterium forms a green film on catheters. Which of the following best explains this phenomenon?

Accepted Answer

The bacterium is forming a biofilm, which is a community of microbes encased in extracellular polymeric substances (EPS).

Question 6

Which of the following is an example of bioremediation?

Accepted Answer

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

Question 7

Which of the following best describes the purpose of using immersion oil with a light microscope?

Accepted Answer

Immersion oil increases the refractive index between the specimen and the objective lens, reducing light refraction and improving resolution.

Question 8

A patient is diagnosed with tuberculosis. Which staining technique would be most appropriate to confirm the presence of the causative organism?

Accepted Answer

Acid-fast stain, because Mycobacterium tuberculosis has a cell wall rich in mycolic acid.

Question 9

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 10

Which of the following is an example of binomial nomenclature written correctly?

Accepted Answer

Escherichia coli

Question 11

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

Accepted Answer

It allows visualization of live, unstained specimens against a dark background.

Question 12

Which of the following best describes the difference between a pure culture and a mixed culture?

Accepted Answer

A pure culture contains only one species of microorganism, while a mixed culture contains two or more species.

Question 13

Which of the following best explains why basic dyes are commonly used to stain bacterial cells?

Accepted Answer

Basic dyes are positively charged and are attracted to the negatively charged surfaces of bacterial cells.

Question 14

A scientist is testing a new antibiotic and follows the scientific method. After making an observation and forming a hypothesis, what is the next step?

Accepted Answer

Design and conduct an experiment to test the hypothesis.

Question 15

Which of the following best describes the relationship between humans and their normal microbiota?

Accepted Answer

Most interactions are mutualistic or commensal, providing benefits to the host or having no effect.

Question 16

Which of the following scenarios best illustrates disruption of normal microbiota?

Accepted Answer

A patient develops a yeast infection after taking broad-spectrum antibiotics.

Question 17

Which of the following is a key difference between transmission electron microscopy (TEM) and scanning electron microscopy (SEM)?

Accepted Answer

TEM is used to view internal structures in 2-D, while SEM is used to view surface structures in 3-D.

Question 18

Which of the following best describes the function of a mordant in staining procedures?

Accepted Answer

A mordant increases the binding of the primary stain to the target structure, enhancing contrast.

Question 19

A microbiologist is culturing bacteria using a streak plate method. What is the main purpose of this technique?

Accepted Answer

To isolate individual colonies and obtain a pure culture.

Question 20

Which of the following best explains why electron microscopes have greater resolution than light microscopes?

Accepted Answer

Electrons have much shorter wavelengths than visible light, allowing for higher resolution.

Chapter 1: Introduction to Microbiology – Comprehensive Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards