Question 1

Which of the following best describes the function of pattern recognition receptors (PRRs) in innate immunity?

Accepted Answer

They recognize and bind to pathogen-associated molecular patterns (PAMPs) on microbes, initiating immune responses.

Question 2

A patient presents with swollen, painful joints and is diagnosed with rheumatoid arthritis. Which immune system malfunction is most likely responsible for this condition?

Accepted Answer

The immune system is attacking the body's own tissues, mistaking them for foreign invaders.

Question 3

Which of the following is NOT a function of the lymphatic system?

Accepted Answer

Transporting oxygen to tissues.

Question 4

Which of the following best explains why the skin is an effective first line of defense against microbial invasion?

Accepted Answer

It consists of tightly packed epithelial cells impregnated with keratin, making it waterproof and difficult for microbes to penetrate.

Question 5

Which of the following is a correct sequence of events during phagocytosis?

Accepted Answer

Chemotaxis, ingestion, phagolysosome formation, destruction, exocytosis

Question 6

A laboratory test shows a high neutrophil count in a patient’s blood. What is the most likely explanation for this finding?

Accepted Answer

The patient is experiencing a bacterial infection.

Question 7

Which of the following statements about fever is TRUE?

Accepted Answer

Fever can slow the growth of bacteria and viruses and increase the activity of white blood cells.

Question 8

Which of the following is a benefit of edema during inflammation?

Accepted Answer

It dilutes toxic substances and allows clotting factors to trap microbes.

Question 9

Which of the following best describes the role of interferons in the immune response?

Accepted Answer

They are proteins produced by certain white blood cells that inhibit viral replication and modulate immune activity.

Question 10

A patient with a genetic deficiency in complement proteins is most likely to experience which of the following?

Accepted Answer

Increased susceptibility to bacterial infections due to impaired lysis of pathogens.

Question 11

Which of the following is an example of a pathogen-associated molecular pattern (PAMP)?

Accepted Answer

Lipopolysaccharide found in the outer membrane of Gram-negative bacteria.

Question 12

Which of the following best explains why normal microbiota are considered a defense mechanism?

Accepted Answer

They compete with pathogens for nutrients and alter the local pH, making it less hospitable for invaders.

Question 13

Which of the following is a correct statement about the movement of lymph in the lymphatic system?

Accepted Answer

Lymph moves in one direction, from tissues toward the heart, and is propelled by skeletal muscle contraction.

Question 14

Which of the following is a function of cytokines in the immune system?

Accepted Answer

They regulate the growth, activation, and differentiation of white blood cells.

Question 15

A patient is exposed to a virus and produces interferon alpha. Which of the following is a likely effect?

Accepted Answer

Activation of natural killer (NK) cells to destroy infected cells.

Question 16

Which of the following best describes the process of diapedesis?

Accepted Answer

The movement of white blood cells from the bloodstream into tissues by squeezing between endothelial cells.

Question 17

Which of the following chemical defenses is found in tears and saliva and is responsible for hydrolyzing peptidoglycan in bacterial cell walls?

Accepted Answer

Lysozyme

Question 18

A patient with a severe burn loses much of their skin barrier. Which of the following is the most immediate risk to their health?

Accepted Answer

Increased susceptibility to microbial infections due to loss of the first line of defense.

Question 19

Which of the following is a correct statement about the complement system?

Accepted Answer

It consists of a cascade of over 50 blood proteins that work together to destroy bacteria and certain viruses.

Question 20

Which of the following is a classic sign of inflammation and its physiological cause?

Accepted Answer

Rubor (redness) caused by increased circulation and vasodilation in injured tissues.

Host Defenses I: Overview and Innate Immunity – Microbiology Study Notes

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