Question 1

Which of the following best describes the difference between innate and adaptive immunity?

Accepted Answer

Innate immunity is present at birth and provides a broad, non-specific defense, while adaptive immunity develops over time and targets specific pathogens.

Question 2

A patient is exposed to a novel virus. Which immune system component is most likely to respond first?

Accepted Answer

Neutrophils

Question 3

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

Accepted Answer

Direct lysis of gram-positive bacteria

Question 4

Which of the following statements about phagocytosis is correct?

Accepted Answer

Phagolysosomes are formed by the fusion of a phagosome and a lysosome.

Question 5

Which of the following is a chemical barrier in the first line of defense?

Accepted Answer

Sebum produced by sebaceous glands

Question 6

A child is born without the ability to produce functional B cells. Which immune response will be most affected?

Accepted Answer

Humoral immunity

Question 7

Which of the following best explains why fever can be beneficial during infection?

Accepted Answer

Fever increases the rate of enzymatic reactions, enhancing immune responses.

Question 8

Which of the following is a property of IgG antibodies?

Accepted Answer

They are the most abundant antibody in blood and tissues.

Question 9

A scientist observes that a patient’s immune cells are unable to leave the bloodstream and enter infected tissues. Which molecule is most likely defective?

Accepted Answer

Adhesion molecules on endothelial cells

Question 10

Which of the following is a correct sequence of events in the inflammatory response?

Accepted Answer

Tissue damage → Release of inflammatory mediators → Vasodilation → Removal of microbes

Question 11

Which of the following is a function of helper T cells (TH)?

Accepted Answer

Produce cytokines to activate B cells and macrophages

Question 12

Which of the following is true regarding antigen presentation and T cell activation?

Accepted Answer

Helper T cells recognize antigens presented on MHC class II molecules.

Question 13

Which of the following is NOT a postulate of the clonal selection theory?

Accepted Answer

All naive B cells that are close in proximity to an antigen begin to differentiate.

Question 14

Which of the following best describes the process of affinity maturation?

Accepted Answer

It is a form of natural selection that increases the effectiveness of antibodies during an infection.

Question 15

Which of the following is a property of T-independent antigens?

Accepted Answer

They are typically polysaccharides with repeating subunits.

Question 16

Which of the following is a likely outcome if the immune system lacks immune tolerance?

Accepted Answer

The immune system will attack self-cells, causing autoimmune diseases.

Question 17

Which of the following is the main function of regulatory T cells (Tregs)?

Accepted Answer

Suppress self-reacting T cells to prevent autoimmune reactions

Question 18

Which of the following is a unique feature of natural killer (NK) cells compared to cytotoxic T cells?

Accepted Answer

NK cells do not require prior activation to kill infected host cells.

Question 19

Which of the following antibody classes is most effective at activating the complement system via the classical pathway?

Accepted Answer

IgM

Question 20

Which of the following best describes the role of cytokines in the immune system?

Accepted Answer

They are signaling proteins that regulate the intensity and duration of immune responses.

Innate and Adaptive Immunity: The Immune System’s Defenses

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