Question 1

Which of the following best describes the process of positive selection during T cell maturation in the thymus?

Accepted Answer

T cells that fail to recognize self-MHC undergo apoptosis.

Question 2

A patient receives an injection of gamma globulin after being bitten by a venomous snake. Which type of immunity is this an example of?

Accepted Answer

Passive, artificially acquired immunity

Question 3

Which antibody class is most abundant in plasma and is responsible for secondary immune responses?

Accepted Answer

IgG

Question 4

What is the primary function of cytotoxic T cells (Tc) in the immune response?

Accepted Answer

Directly attack and kill infected or cancerous cells

Question 5

Which of the following is TRUE regarding antigen-presenting cells (APCs)?

Accepted Answer

APCs display antigen fragments to T cells for recognition.

Question 6

A child develops immunity after recovering from chickenpox. Which type of immunity is this?

Accepted Answer

Active, naturally acquired immunity

Question 7

Which equation best represents the relationship between antibody concentration and time during a secondary immune response?

Accepted Answer

$$A(t) = A_{max} \left(1 - e$$^{-kt}$$\right)$$

Question 8

Which of the following is a key difference between Class I and Class II MHC proteins?

Accepted Answer

Class II MHC proteins present exogenous antigens and are recognized by helper T cells.

Question 9

Which defensive mechanism is used by antibodies to enhance phagocytosis by marking dangerous parts of bacterial exotoxins or viruses?

Accepted Answer

Neutralization

Question 10

A newborn receives antibodies from its mother through breast milk. What type of immunity is this?

Accepted Answer

Passive, naturally acquired immunity

Question 11

Which cytokine is primarily responsible for promoting inflammation and T cell activation, and acts as a pyrogen that causes fever?

Accepted Answer

Interleukin-1 (IL-1)

Question 12

What is the outcome of clonal deletion during B cell maturation?

Accepted Answer

Self-reactive B cells undergo apoptosis.

Question 13

Which of the following best explains why HIV infection leads to immunodeficiency?

Accepted Answer

HIV infects and destroys helper T cells, paralyzing the immune response.

Question 14

Which of the following is NOT a function of regulatory T cells (TR)?

Accepted Answer

Directly attack and kill infected cells

Question 15

Which process describes the formation of antigen-antibody complexes that result in the clumping of cell-bound antigens?

Accepted Answer

Agglutination

Question 16

A patient with type 1 diabetes mellitus has an autoimmune disease. Which of the following best describes the underlying mechanism?

Accepted Answer

The immune system loses ability to distinguish self from foreign, producing autoantibodies and sensitized cytotoxic T cells that destroy body tissues.

Question 17

Which of the following is TRUE about the primary immune response?

Accepted Answer

It requires 3-6 days for B cells to proliferate and differentiate.

Question 18

Which of the following best describes the structure of an antibody?

Accepted Answer

It consists of four polypeptide chains, each with constant and variable regions, forming antigen-binding sites.

Question 19

Which of the following is a real-world example of artificially acquired active humoral immunity?

Accepted Answer

Receiving a vaccine containing dead or attenuated pathogens

Chapter 21: The Immune System – Adaptive Immunity and Lymphocyte Function

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