Question 1

Which of the following best describes the function of fimbriae in bacteria?

Accepted Answer

They help bacteria adhere to surfaces and host tissues.

Question 2

A microbiologist is using a compound light microscope with an ocular lens of $10	imes$ and an objective lens of $40	imes$. What is the total magnification?

Accepted Answer

$400	imes$

Question 3

Which component is unique to the Gram-negative bacterial cell wall and is responsible for its toxicity?

Accepted Answer

Lipopolysaccharide (LPS)

Question 4

Which of the following best explains why Gram staining differentiates between Gram-positive and Gram-negative bacteria?

Accepted Answer

Gram-positive bacteria have a thicker peptidoglycan layer that retains the crystal violet stain.

Question 5

Which of the following is NOT a correct example of aseptic technique in a clinical laboratory?

Accepted Answer

Leaving culture plates open to the air while working.

Question 6

A patient is diagnosed with tuberculosis. Which genus of bacteria is responsible for this disease, and what unique cell wall component does it possess?

Accepted Answer

Mycobacterium; mycolic acid

Question 7

Which of the following best defines a pathogen?

Accepted Answer

A microorganism that causes disease in its host.

Question 8

Which of the following statements about prokaryotic ribosomes is correct?

Accepted Answer

They are 70S in size and consist of 50S and 30S subunits.

Question 9

A microbiologist wants to culture strict obligate aerobes. Which of the following conditions must be provided?

Accepted Answer

An environment with abundant oxygen.

Question 10

Which of the following best describes the process of pasteurization?

Accepted Answer

Reducing microbial load in liquids by heating at $63^\circ$C for 30 minutes or $72^\circ$C for 15 seconds.

Question 11

Which of the following is a correct example of reducing media and its use?

Accepted Answer

Thioglycollate broth; used for culturing anaerobic bacteria.

Question 12

Which of the following best describes the role of plasmids in genetic engineering?

Accepted Answer

They are used as vectors to transfer foreign genes into host cells.

Question 13

A scientist is using a basic dye to stain bacterial cells. Which of the following best explains why basic dyes are effective for this purpose?

Accepted Answer

Basic dyes are positively charged and bind to the negatively charged bacterial cell surface.

Question 14

Which of the following best describes the concept of total magnification in microscopy?

Accepted Answer

It is the product of the magnifications of the ocular and objective lenses: $	ext{Total Magnification} = 	ext{Ocular Magnification} 	imes 	ext{Objective Magnification}$

Question 15

Which of the following is a correct statement about the five kingdom classification system?

Accepted Answer

It classifies all living organisms into Monera, Protista, Fungi, Plantae, and Animalia.

Question 16

Which of the following best describes the function of endospores in bacteria?

Accepted Answer

They allow bacteria to survive harsh environmental conditions.

Question 17

A hospital is experiencing an outbreak of a disease. The number of new cases per 1,000 people in a given time period is referred to as:

Accepted Answer

Morbidity rate

Question 18

Which of the following is a correct example of a strict obligate aerobe?

Accepted Answer

Mycobacterium tuberculosis

Question 19

Which of the following best describes the arrangement of flagella in peritrichous bacteria?

Accepted Answer

Flagella distributed over the entire surface of the cell

Question 20

Which of the following statements about the glycocalyx is correct?

Accepted Answer

It is a sticky, gelatinous layer that helps bacteria adhere to surfaces and evade the immune system.

Comprehensive Study Notes for Introductory Microbiology

Study Guide - Practice Questions

Study Guide - Flashcards