Question 1

Which of the following best describes the difference between active and passive humoral immunity?

Accepted Answer

Active immunity results from exposure to an antigen and the subsequent production of antibodies, while passive immunity results from the transfer of antibodies produced by another individual.

Question 2

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

Accepted Answer

Naturally acquired passive immunity

Question 3

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

Accepted Answer

IgG

Question 4

What is the function of the variable (V) region of an antibody molecule?

Accepted Answer

It binds to specific antigens at the antigen-binding site.

Question 5

Which of the following is TRUE regarding the primary and secondary humoral immune responses?

Accepted Answer

The secondary response is faster and produces more IgG than the primary response.

Question 6

A patient receives an injection of gamma globulin after exposure to hepatitis. What type of immunity is this?

Accepted Answer

Artificially acquired passive immunity

Question 7

Which antibody class is found as a dimer in mucus, saliva, tears, and milk, and helps prevent pathogen adherence to epithelia?

Accepted Answer

IgA

Question 8

What is the role of helper T cells (TH cells) in adaptive immunity?

Accepted Answer

They secrete interleukins to stimulate and coordinate the activity of other immune cells.

Question 9

Which process allows antigen-presenting cells (APCs) to display fragments of antigens on their surface for recognition by T cells?

Accepted Answer

Phagocytosis followed by presentation with MHC proteins

Question 10

A person with AIDS has a helper T cell count less than 200 cells/μL. What is the primary consequence of this condition?

Accepted Answer

High susceptibility to infections due to impaired immune response

Question 11

Which of the following best explains why proteins are more antigenic than lipids?

Accepted Answer

Proteins have more complex structures and multiple epitopes.

Question 12

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

Accepted Answer

To directly attack and destroy infected or abnormal cells

Question 13

Which of the following is a mechanism by which antibodies help eliminate pathogens?

Accepted Answer

Antibodies neutralize toxins and viruses by binding to them.

Question 14

A person develops an autoimmune disease after a viral infection. Which mechanism could explain this phenomenon?

Accepted Answer

The virus alters self-antigens, causing the immune system to attack them.

Question 15

Which equation best represents the relationship between antigen exposure and antibody production in a secondary immune response?

Accepted Answer

$$	ext{Antibody Production} = k 	imes 	ext{Memory B Cells} 	imes 	ext{Antigen Concentration}$$

Question 16

Which of the following is a plausible outcome if B cells that react to self-antigens are not destroyed during development?

Accepted Answer

The individual may develop autoimmune diseases.

Question 17

Which antibody class is most likely to be elevated during an acute allergic reaction?

Accepted Answer

IgE

Question 18

Which organ is essential for the maturation of T cells?

Accepted Answer

Thymus

Question 19

What is the primary role of the Major Histocompatibility Complex (MHC) in adaptive immunity?

Accepted Answer

To present antigen fragments on the cell surface for recognition by T cells

Adaptive Immunity: Mechanisms and Disorders

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