Q: Which of the following equations best represents the relationship between plasma and serum?

$$\text{serum} = \text{plasma} - \text{fibrinogen}$$

Q: A patient with a fever has elevated levels of IL-1, IL-6, and TNF. These cytokines stimulate the production of which molecule that resets the hypothalamic thermostat?

Prostaglandin E2 ($$\text{PGE}_2)$$

Question 1

Which of the following best describes the primary function of tight junctions in epithelial tissues?

Accepted Answer

They rivet adjacent cells together, preventing or limiting material exchange through the spaces between them.

Question 2

A patient with a genetic defect in desmosomes is most likely to experience which of the following symptoms?

Accepted Answer

Frequent skin blistering due to loss of cell adhesion.

Question 3

Which of the following is a mechanical defense that helps prevent microbial colonization in the urinary tract?

Accepted Answer

Flushing action of urine.

Question 4

The mucociliary escalator is damaged in a patient with cystic fibrosis. What is the most likely consequence?

Accepted Answer

Increased risk of lower respiratory tract infections.

Question 5

Which of the following chemical mediators is produced by resident skin microbiota and contributes to the skin's mildly acidic environment?

Accepted Answer

Oleic acid

Question 6

A patient is prescribed broad-spectrum antibiotics, which disrupt their gut microbiota. What is a potential consequence of this disruption?

Accepted Answer

Increased susceptibility to Clostridioides difficile infection.

Question 7

Which of the following antimicrobial peptides is primarily produced by sweat glands and acts by disrupting membrane integrity and ion channels?

Accepted Answer

Dermcidin

Question 8

Which plasma protein mediator is most directly involved in opsonization, enhancing phagocytosis of pathogens?

Accepted Answer

Complement C3b

Question 9

A pathogen is recognized by a phagocyte through its peptidoglycan. Which receptor is most likely involved in this recognition?

Accepted Answer

Toll-like receptor (TLR)

Question 10

Which of the following equations best represents the relationship between plasma and serum?

Accepted Answer

$$	ext{serum} = 	ext{plasma} - 	ext{fibrinogen}$$

Question 11

Which cytokine class is most specifically involved in recruiting leukocytes to sites of infection?

Accepted Answer

Chemokines

Question 12

A patient with a fever has elevated levels of IL-1, IL-6, and TNF. These cytokines stimulate the production of which molecule that resets the hypothalamic thermostat?

Accepted Answer

Prostaglandin E2 ($$	ext{PGE}_2)$$

Question 13

Which of the following is a consequence of excessive neutrophil extracellular trap (NET) formation?

Accepted Answer

Thrombosis and tissue damage

Question 14

Which of the following is NOT a function of acute-phase proteins?

Accepted Answer

Stimulating antibody production

Question 15

Which of the following best describes the action of interferon-α and interferon-β?

Accepted Answer

They inhibit viral replication by halting mRNA and protein synthesis in neighboring cells.

Question 16

Which of the following is a physical defense that prevents microbes from reaching the central nervous system?

Accepted Answer

Blood–brain barrier with tight junctions

Question 17

Which of the following is a correct sequence for the process of phagocytosis?

Accepted Answer

Pathogen recognition → Pseudopod formation → Phagosome formation → Phagolysosome fusion → Pathogen degradation

Question 18

Which of the following is a major benefit of fever during infection?

Accepted Answer

Enhances leukocyte activity and inhibits growth of mesophilic pathogens

Question 19

Which of the following is a characteristic of chronic inflammation?

Accepted Answer

Formation of granulomas and persistent tissue damage

Question 20

Which of the following is a correct description of the classical complement pathway?

Accepted Answer

It is initiated by antibody binding to a pathogen, activating the C1 complex.

Innate Immunity: The First Line of Defense in Microbiology

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