Question 1

Which of the following best describes the difference between sterilization and disinfection in microbial control?

Accepted Answer

Sterilization removes all forms of microbial life, including endospores, while disinfection eliminates only pathogenic microorganisms on inanimate objects.

Question 2

A hospital uses an autoclave to sterilize surgical instruments. Which physical method of microbial control is being applied, and what is the principle behind its effectiveness?

Accepted Answer

Moist heat; it denatures proteins and destroys membranes by using pressurized steam at $$121^\circC.$$

Question 3

Which of the following is an example of a chemical method of microbial control that disrupts cell membranes and denatures proteins?

Accepted Answer

Alcohols, such as ethanol and isopropanol

Question 4

Which of the following best defines selective toxicity in the context of antimicrobial drugs?

Accepted Answer

The ability of a drug to target microbial cells without harming host cells.

Question 5

A patient is prescribed a beta-lactam antibiotic. Which mechanism of action is most likely responsible for its antimicrobial effect?

Accepted Answer

Inhibition of cell wall synthesis by interfering with peptidoglycan cross-linking.

Question 6

Which of the following is NOT a common mechanism by which bacteria develop resistance to antibiotics?

Accepted Answer

Increasing the permeability of the cell membrane to allow more drug entry.

Question 7

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

Accepted Answer

Mutualism, where both the host and the microbiota benefit.

Question 8

Which of the following conditions can enable resident microbiota to become opportunistic pathogens?

Accepted Answer

Suppression of the immune system, such as during chemotherapy.

Question 9

A patient acquires an infection after a surgical procedure in a hospital. This is best classified as which type of infection?

Accepted Answer

Health-care associated infection (HAI)

Question 10

Which of the following statements about innate immunity is correct?

Accepted Answer

It is non-specific and present from birth, providing immediate defense against pathogens.

Question 11

Which of the following cells are capable of performing phagocytosis as part of the innate immune response?

Accepted Answer

Neutrophils and macrophages

Question 12

During the process of diapedesis, which of the following occurs?

Accepted Answer

Leukocytes move out of blood vessels into surrounding tissues in response to infection.

Question 13

Which of the following best explains why adaptive immunity is considered 'specific'?

Accepted Answer

It targets particular antigens with tailored responses involving B and T lymphocytes.

Question 14

Which of the following statements about Major Histocompatibility Complex (MHC) molecules is correct?

Accepted Answer

All nucleated cells express MHC I, while only antigen-presenting cells express MHC II.

Question 15

Which of the following best describes the function of plasma cells in the adaptive immune response?

Accepted Answer

They secrete large quantities of antibodies specific to the encountered antigen.

Question 16

A patient receives an injection of pre-formed antibodies after exposure to rabies. Which type of acquired immunity is this an example of?

Accepted Answer

Artificially acquired passive immunity

Question 17

Which of the following best defines herd immunity?

Accepted Answer

A form of indirect protection from infectious disease that occurs when a large percentage of a population is immune.

Question 18

Which of the following is a key advantage of live attenuated vaccines compared to inactivated vaccines?

Accepted Answer

They often induce stronger and longer-lasting immunity with fewer booster doses.

Question 19

Which principle underlies all serological tests used in immunoassays?

Accepted Answer

The specific binding of antibodies to their corresponding antigens.

Question 20

A patient with a genetic deficiency in complement proteins is more susceptible to which of the following?

Accepted Answer

Recurrent bacterial infections due to impaired lysis and opsonization.

Microbiology Study Guide: Microbial Control, Infection, Immunity, and Immunoassays (Chapters 9, 10, 14, 15, 16, 17)

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