Question 1

Which of the following statements best explains why microbiologists group bacteria, archaea, algae, fungi, protozoa, and viruses together, despite their differences?

Accepted Answer

They are all too small to be seen without a microscope and are studied using similar techniques.

Question 2

A patient develops pneumonia caused by Pneumocystis jirovecii after being diagnosed with AIDS. This is an example of which type of infectious disease?

Accepted Answer

Opportunistic infectious disease

Question 3

Which of the following best describes the role of lactic acid bacteria, such as Lactobacillus acidophilus, in the human body?

Accepted Answer

They are part of the resident microbiota and contribute to microbial antagonism and vitamin production.

Question 4

Which of the following is NOT a characteristic of viruses?

Accepted Answer

They are made of cells with a nucleus.

Question 5

A hospital outbreak of Salmonella is traced to contaminated chicken served in the cafeteria. What is the most accurate classification of the mode of transmission?

Accepted Answer

Vehicle transmission (foodborne)

Question 6

Which of the following best describes the function of lysozyme in human tears, saliva, and perspiration?

Accepted Answer

It is a chemical barrier that breaks down bacterial cell walls.

Question 7

Which of the following is an example of a disease caused by a pathogenic bacterium that produces an exotoxin?

Accepted Answer

Tetanus

Question 8

A mother with active tuberculosis transmits the infection to her newborn during childbirth. This is an example of:

Accepted Answer

Vertical transmission (a type of direct contact transmission)

Question 9

Which of the following best explains why zoonoses are difficult to control?

Accepted Answer

They involve animal reservoirs, making eradication challenging.

Question 10

Which of the following is a benefit of fever in the context of innate immunity?

Accepted Answer

It enhances the activity of immune cells and inhibits the growth of some pathogens.

Question 11

Which of the following best describes the process of phagocytosis?

Accepted Answer

The engulfment and digestion of pathogens by specialized cells.

Question 12

A patient is diagnosed with a chronic carrier state of hepatitis B virus. Which of the following best describes this reservoir?

Accepted Answer

Human reservoir (chronic carrier)

Question 13

Which of the following is a correct example of microbial antagonism?

Accepted Answer

Resident microbiota occupying space and preventing pathogen colonization.

Question 14

Which of the following is a correct statement about Koch’s postulates?

Accepted Answer

They establish that a specific microorganism causes a specific disease.

Question 15

Which of the following is a function of the complement system in innate immunity?

Accepted Answer

To enhance phagocytosis and lyse pathogens.

Question 16

A bacterial pathogen avoids phagocytosis by producing a capsule. Which of the following best explains how the capsule helps the pathogen evade the immune system?

Accepted Answer

The capsule makes the bacterial surface slippery, preventing phagocyte attachment.

Question 17

Which of the following best describes the difference between exotoxins and endotoxins?

Accepted Answer

Exotoxins are secreted proteins, while endotoxins are lipopolysaccharides (LPS) found in the outer membrane of Gram-negative bacteria.

Question 18

Which of the following equations best represents the process of lactic acid fermentation performed by lactic acid bacteria?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$ \rightarrow 2C_3H_6O_3}$$

Question 19

Which of the following is an example of a mechanical barrier in the innate immune system?

Accepted Answer

The movement of cilia in the respiratory tract

Question 20

Which of the following best describes the role of E. coli in the human large intestine?

Accepted Answer

It is a resident microbiota that synthesizes vitamin K and some B vitamins for the host.

Question 21

A person develops a secondary infection after being treated for influenza. Which of the following best describes a secondary infection?

Accepted Answer

An infection that follows and is a result of a primary infection.

Microbiology Exam 1 Study Guide: Introduction, Infection, and Innate Immunity

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