Question 1

Which of the following is NOT a major function of the immune system?

Accepted Answer

It produces hormones to regulate metabolism.

Question 2

Which physical barrier is most responsible for preventing pathogen entry into the body?

Accepted Answer

The skin

Question 3

Gastric secretions in the stomach contribute to immunity primarily by:

Accepted Answer

Lowering pH to destroy ingested pathogens

Question 4

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

Accepted Answer

Innate responses are non-specific and rapid, while adaptive responses are specific and slower.

Question 5

Which immune cell is primarily responsible for antigen presentation to T cells?

Accepted Answer

Dendritic cell

Question 6

A patient is unable to produce IgG antibodies. Which immune function would be most impaired?

Accepted Answer

Long-term protection against bacterial and viral infections

Question 7

Which of the following is a chemical barrier involved in the innate immune response?

Accepted Answer

Lysozyme in tears and saliva

Question 8

What is the primary role of MHC-I molecules in immunity?

Accepted Answer

Presenting endogenous antigens to cytotoxic T cells

Question 9

Which equation best represents the relationship between antigen concentration ($[Ag]$) and antibody binding ($B$) in a simple binding reaction?

Accepted Answer

$B = \frac{[Ag] \cdot [Ab]}{K_d + [Ag]}$

Question 10

A person receives a vaccine and develops immunity. This is an example of:

Accepted Answer

Active artificial immunity

Question 11

Which cell type is most involved in the cell-mediated adaptive immune response?

Accepted Answer

Cytotoxic T lymphocyte

Question 12

Which of the following best explains why the adaptive immune response is slower than the innate response?

Accepted Answer

It requires clonal selection and expansion of specific lymphocytes.

Question 13

Which process involves the removal of pathogens by engulfment and digestion within immune cells?

Accepted Answer

Phagocytosis

Question 14

A patient with a genetic defect in complement proteins would most likely have problems with:

Accepted Answer

Opsonization and lysis of pathogens

Question 15

Which of the following is a mechanical barrier to infection?

Accepted Answer

Ciliated epithelium in the respiratory tract

Question 16

During a viral infection, which immune process is most important for eliminating infected cells?

Accepted Answer

Cytotoxic T cell-mediated killing

Question 17

Which of the following best describes passive immunity?

Accepted Answer

Transfer of antibodies from another individual

Question 18

Which immune molecule is most likely to be found in secretions such as saliva and tears?

Accepted Answer

IgA

Question 19

If a pathogen evades the physical and chemical barriers, which is the next line of defense?

Accepted Answer

Innate immune response

Question 20

Which of the following best describes the role of antigen-presenting cells (APCs) in immunity?

Accepted Answer

They process and present antigens to T cells to initiate adaptive responses.

The Immune System: Structure, Function, and Mechanisms

Study Guide - Practice Questions